Best Hydration Packs for Running of 2024 – iRunFar

Maggie Guterl tests an UltrAspire hydration pack outside of Durango, Colorado. Photo: iRunFar/Eszter Horanyi

There’s a lot to consider when looking for the best hydration pack for running. Not only does the right pack need to carry your water, snacks, and clothing on a run, it needs to fit well, not bounce on your back as you move, and not cause you to overhead. It also needs to have a convenient set of pockets to keep your gear organized.

The running hydration pack, also called a running vest, is a vital accessory in nearly any runner’s gear collection. Whether you’re going out for an hour in the heat and need to carry water or all day in the mountains where you need a lot of gear, there’s a pack for every situation. While you can get away without a pack for a shorter run, they can help you carry food, hydration, phones, first aid, layers, trekking poles, and more. A good pack can hold what you need to make a run a safe and happy experience.

Choosing the right pack can be daunting, with packs ranging from minimalist to those that can carry everything you need for a full-day unsupported run through the mountains. Our team of trail runners scoured the market for the best packs available and took the most promising of them out on all sorts of terrain to test their comfort, functionality, and durability so that we can help make your search for the perfect pack easier. We chose the Salomon Adv Skin 5 unisex running vest as our favorite small pack and the UltrAspire Alpha 5.0 Race Vest for runs requiring more gear. When it came to carrying everything and the kitchen sink, we went with the Salomon Adv Skin 12 unisex running vest.

For more background information about the best hydration packs for trail running, see our buying advice, testing methodology, and frequently asked questions below the picks.

Best Hydration Packs for Running

Best Small-Capacity (1 to 5 Liters) Hydration Packs for Running

Best Medium-Capacity (6 to 11 Liters) Hydration Packs for Running

Best Large-Capacity (12 to 15 Liters) Hydration Packs for Running

Other Top Hydration Packs for Running

A properly sized hydration pack can carry everything you need for a mountain run. Photo: iRunFar/Eszter Horanyi

Best Small-Capacity (1 to 5 Liters) Hydration Packs for Running

Pros:

• Stretchy pockets can fit a lot of gear securely, exceeding the stated capacity
• Sensifit material and elastic chest straps fit tightly to prevent bouncing without compressing your body
• Flask and bladder pockets allow for expandable fluid-carrying capacity for longer runs

Cons:

• The panel in the rear compartment traps heat and increases sweating on hot days
• Straws in the women’s version can flop around and may need to be trimmed
• Mesh lining can be scratchy on bare skin

Any search for the best trail running hydration pack will lead to multiple mentions of Salomon packs, and after months of testing, our testers wholeheartedly agree that the Salomon Adv Skin 5 unisex running vest and Salomon Adv Skin 5 women’s running vest have earned their place at the top of the best low-volume pack pile.

The two front pockets carry a pair of 500-milliliter soft flasks included with the vest. Additional stretchy pockets overlay these flask pockets, and a smaller zip pocket on one side securely holds small items. The flasks sit high on the chest in the unisex version of the pack and are easy to drink out of without removing them from their pockets. An elastic loop secures the top of the flask so that it doesn’t fall into the pocket as it empties.

The additional front pockets can fit plenty of smaller items like gloves, a buff, gels or chews, or lip balm, and they can also fit most cellphones for quick access. The rear has one large compartment with a separate hydration bladder sleeve that fits a 1.5-liter bladder. This compartment includes a panel to protect your gear from moisture, either from sweat or the hydration bladder, though some testers found that this extra layer of fabric increased heat retention on their back during hot runs.

A pass-through stretch sleeve covers the lower back of the pack and is an ideal place to stash a jacket, a hat, or smaller gear in an accessible place. Salomon’s Sensifit construction includes well-placed stretch panels so the pack can fit an impressive amount of gear comfortably and securely without it shifting, bouncing, or feeling too compressive. This pack easily fits the same amount of gear, or potentially more, than many of the higher-capacity packs we tested, and our testers have used it for multiple supported ultramarathons and six-plus hour training runs in the forests of New England with ease.

An elastic sternum strap has multiple attachment points to personalize fit and make adjustments on the fly easily. A single pull-through toggle tightens and loosens the fit. There are several ways to carry trekking poles with multiple elastic cords on the front and back of this pack. Salomon’s pole quiver is also a popular option that works well with this pack. An attached whistle on the front and a key clip in the rear compartment are small but helpful details.

The Salomon Adv Skin 5 is available in a unisex fit and a women’s-specific version. The women’s fit has a similar pocket setup but positions the soft flask pockets lower to avoid pressure over the chest. The flasks come with longer drinking straws so that they are reachable without removing the flasks. This difference changes the fit and feel of the pack significantly, and the best fit for any individual just comes down to personal preference. Most of our female testers preferred Salomon’s unisex pack, but runners with larger chests may appreciate the women’s fit.

To learn more, read our in-depth Salomon Adv Skin 5 review.

Gear Capacity: 5 liters | Liquid Capacity: 2.5 liters | Hydration Carrying Method: Two 500-milliliter flasks (included) in front sleeves, 1.5-liter bladder (sold separately) in rear | Model Options: Unisex and women’s-specific model

Shop the Salomon Adv Skin 5 unisex running vestShop the Salomon Adv Skin 5 women’s running vest

Pros:

• Generous liquid-carrying capacity for its size
• Easily repositioned sternum straps to dial in the fit

Cons:

• Material is thicker and heavier than some other packs
• Hydration bladder tubing can only be routed to the right side

The Osprey Duro 1.5 and the Osprey Dyna 1.5, the women’s version, are 1.5-liter, low-volume, race-ready packs with everything you need for short and fast days on the trail. A rear zip compartment fits the included 1.5-liter hydration reservoir, and two large front stretch pockets can fit nutrition, small bits of gear, or Osprey’s 500-milliliter or 360-milliliter soft flasks, which are sold separately. Our testers noted that the rear pocket could not fit additional gear if the hydration bladder is used, but there is an exterior bungee cinch cord to carry a jacket or extra layer. Two stretch pockets under the arms can fit a buff, a hat, gloves, or other smaller items. There is also a smaller front zip pocket to hold a few other small items securely. The rear hydration bladder compartment has a diagonal zipper opening that only allows the tubing to route over the right shoulder, something to keep in mind if you prefer it on the left.

The sternum strap is secured with plastic snaps that clip on each shoulder strap instead of having a center buckle, making it easy to adjust their positioning to your comfort. Our testers found arm holes to run a little on the small side, so if you have broader arms or shoulders, you may need to size up. The material is a little thicker and heavier than some of the other tested packs but is very durable while maintaining breathability.

There is a safety whistle on the front and a place to attach trekking poles when you’re not actively using them. For a small-capacity pack, we found it to include a lot of thoughtful details and a hydration capacity on par with many larger packs.

If you love the fit and function of this pack but are looking for something with more gear storage capacity, Osprey offers a six-liter version of the Duro and Dyna that you can learn more about in our Osprey Dyna 6/Duro 6 review.

Gear Capacity: 1.5 liters | Liquid Capacity: 2.5 liters | Hydration Carrying Method: 1.5-liter hydration bladder (included) and can fit two 360-milliliter or 500-milliliter soft flasks in front pockets (sold separately) | Model Options: Gender-specific, Duro (men’s) and Dyna (women’s)

Shop the Osprey Duro 1.5Shop the Osprey Dyna 1.5

Pros:

• Lightweight material
• Actual storage capacity exceeds the stated four liters
• Water-resistant pockets to keep a phone or other small items protected

Cons:

• Pricey, particularly for this capacity range
• It runs big, may need to size down from your usual size
• No hydration bladder included, which adds cost to an already expensive pack

The Nathan Pinnacle 4 Liter Hydration Race Vest and the Nathan Pinnacle 4 Liter Women’s Hydration Race Vest are breathable, lightweight running vests that provide easy access to hydration and gear for shorter trail runs and well-supported ultras. This hydration vest features a familiar front pocket with two larger stretchy sleeves to fit the two included 500-milliliter flasks. These flasks feature extended drinking straws and a firm piece of plastic built in to help them maintain their shape and keep them from sinking into the pocket when empty. Our testers didn’t experience any flopping with the straws and flasks, even when empty, which was surprising given the long straws. The front storage also includes a water-resistant zipper pocket on each side that can fit most cell phones. The pocket is tucked behind the flask pocket, which our testers found worked well but put increased pressure on the ribs with a phone in the pocket and a full soft flask on top of it.

The stretchy rear compartment can fit a 1.5-liter bladder, and there is also a vertical trekking pole pocket that our testers found worked well and kept their poles from bouncing. Small stretch pockets over the front flask sleeves, stretch compartments under the arms, and two kangaroo pockets across the lower back provide additional storage for your long-run or race-day needs.

The hydration pack is made of a similar but lighter-weight fabric than its predecessor, the VaporKrar and VaporHowe. It also has a modified shape with a longer back than previous models to help disperse gear. Our testers found the fabric soft and comfortable against the body. The nylon sternum straps feature standard buckle closure and are mounted on a sliding rail that allows you to easily adjust their position up and down the front of the pack. There is both a unisex and women-specific model, and we found both to run on the larger side. You can use a measurement-based sizing guide on Nathan’s website to help you determine the correct size, but if you’re between sizes, you probably want to size up. A larger 12-liter version of this pack is available for those who need to carry more gear for longer runs.

Gear Capacity: 4 liters | Liquid Capacity: 2.8 liters (can fit a standard 1.5-liter bladder or Nathan’s 1.6-liter or 1.8-liter hourglass-shaped bladders) | Hydration Carrying Method: Two 500-milliliter front flasks with straws (included), rear hydration bladder up to 1.8 liters (sold separately) | Model Options: Unisex and women’s-specific models

Shop the Nathan Pinnacle 4 Liter Hydration Race VestShop the Nathan Pinnacle 4 Liter Women’s Hydration Race Vest

Best Medium-Capacity (6 to 11 Liters) Hydration Packs for Running

Pros:

• Comfortable harness and easy-to-use front cinch closure eliminate pressure points and keep the pack stable
• Less compressive fit than other brands
• Many thoughtful details and well-designed storage compartments
• Affordable and good value

Cons:

• Heavier material increases weight and retains some heat
• Fit is on the larger side and may not accommodate smaller bodies
• Secure phone storage is not convenient

As a mid-volume pack, the UltrAspire Alpha 5.0 Race Vest can bridge the gap between wanting to carry the bare minimum but not quite needing the capacity for a full-day unsupported journey. This pack is an excellent size for a three-plus hour run or a supported ultramarathon where you may need to go a couple of hours between aid stations but don’t need to carry your whole day’s nutrition and water. It’s also a great option for ultras that don’t have an extensive gear list. This pack’s six-liter capacity and thoughtful features made it our tester’s top pick in this category.

UltrAspire’s ErgoFit harness design has curved and angled shoulder straps for comfort and also lowers the center of gravity of the pack to reduce fatigue on the neck, improve weight distribution and stability, and enhance the arm’s range of motion. Our smaller testers found that this pack initially felt large and a little loose but stayed stable with no bounce, even if the front elastic straps were not tight. This allowed for good chest expansion when breathing and eliminated that overly compressed tight feeling common with many other packs.

The front of the pack has two large pockets that can fit quick-access items like food and gels and hold a pair of 500-milliliter soft flasks or UltrAspire’s flexible hybrid bottles. Since the pockets are lower on the chest than on many other hydration vests, the bottles or flasks must be removed to take a drink. While this may be an annoyance for some, the pockets are wide enough to make reinserting the flasks easy. We decided that it wasn’t a deal-breaker for us. Zippered side pockets under the arms were a favorite feature for our testers, who found them great for keeping items secure but easy to reach.

The rear compartment spans the length of the pack, providing extra storage capacity, and fits the included two-liter hydration bladder in a separate sleeve with a removable Mylar-insulated insert to maintain your liquids’ temperature. A magnetic-closure pass-through pocket and elastic cinch cord provide additional quick-access rear storage for an extra layer or extra snack. Elastic shock cord loops on the bottom of the pack are the only way to attach trekking poles, and we found these to be a bit bouncy and not as stable as other packs.

The hydration pack has a lightweight honeycomb mesh next to the body that wicks moisture well, but the other vest materials are thicker when compared with similar packs. This may improve its long-term durability but make the pack heavier. The profile of this pack can feel long for smaller runners or those with a shorter torso.

The elastic cinch cord sternum closure is fixed but quite comfortable with a simple hook, which minimizes fumbling with a complicated buckle with tired or cold fingers. A small magnetic-closure water-resistant pocket is perfect for pills or salt tabs, and a stretchy sleeve with a cinch closure on the left shoulder is made for a cellphone. This pocket is also an excellent place to stash a gel or chews. For those of us who hate bouncing cords, the front left pocket has a small pass-through to tuck the end of the shock cord away once it is secured and tightened, which is a nice touch. As one of our testers succinctly said, “UltrAspire nails the little things.”

You can also read our in-depth UltrAspire Alpha 5.0 Race Vest review to learn more.

Gear Capacity: 6 liters | Liquid Capacity: 3 liters | Hydration Carrying Method: 2-liter hydration bladder (included) and can fit two 500-milliliter flasks or UltrAspire bottles in front pockets (sold separately) | Model Options: Unisex

Shop the UltrAspire Alpha 5.0 Race Vest

Pros:

• Simple chest buckle and elastic side cords for easy adjustments
• Harness design eliminates bounce without feeling tight or constrictive
• Lightweight and breathable

Cons:

• Flasks have narrow openings that are hard to refill, and straws can shift and bounce around
• Rear storage is not easily accessible with the pack on
• The only pole-carrying option is across the front of the pack

The Swedish company USWE (pronounced “you-swii”) originates in the off-road motorcycle and bicycle world, and their foray into running hydration packs includes the USWE Pace 8L Trail Running Vest. Their experience and innovation for other outdoor activities have led to some unique features for this vest that made it stand out in the mid-volume pack category.

This eight-liter pack features USWE’s signature “No Dancing Monkey” harness system, providing a secure fit with no bounce. The front closure system is unique, with one large circular buckle that our testers praised for its simplicity and ease of use. The pack’s adjustment points are elastic draw cords on the sides that cinch to tighten the fit while allowing some breathing and movement expansion. The material is very lightweight and stretchy, comfortable when on, and expandable to accommodate gear. A bonus is their Polygiene material treatment, which prevents odor and improves the pack’s longevity.

Two front pockets carry the included pair of 500-milliliter soft flasks. These are oriented lower on the body and have attached drinking straws to allow for sipping on the go without having to remove the flask. The flasks have relatively small openings, which we found inconvenient for refilling, especially if using an electrolyte powder or drink mix. Two stretch pockets over the flask pockets are nicely expandable and can fit a cell phone, gels, and other smaller items.

The rear compartment can fit a two-liter bladder (not included) and utilizes two pull-tight straps on the shoulders to compress the bladder, securing it and preventing movement and bouncing. Two zippered pockets along the lower rear of the pack provide secure storage. These overlie each other and can be challenging to reach with the pack on, making them less convenient than an open-ended kangaroo-style pocket. One of these compartments has a zipper opening on the bottom, which could lead to gear falling out if it is not fully zipped. There is reduced storage space underneath the arms due to the pack’s cinch system.

The trekking pole attachment sits diagonally across the front of the pack, which can interfere with the storage pockets and may be uncomfortable for runners with narrow builds or larger chests. At iRunFar, we also discourage the storage of trekking poles on the front of the body due to the risk of injury in case of a fall.

If you like the fit and design of this vest but are looking for a lower-capacity race-ready vest, USWE also makes a two-liter version with the same design and fit but eliminates the larger rear pocket. You can check it out at our USWE Pace 2 Running Vest review.

Gear Capacity: 8 liters | Liquid Capacity: 3 liters | Hydration Carrying Method: Two 500-milliliter straw soft flasks (included) and can fit a 2-liter bladder (sold separately) in the rear | Model Options: Unisex

Shop the USWE Pace 8L Trail Running Vest

Best Large-Capacity (12 to 15 Liters) Hydration Packs for Running

Pros:

• Just as comfortable full as it is with minimal gear
• Stretch compartments hold a lot of gear and distribute weight well
• Stretch panels conform snugly to the body without compressing

Cons:

• Flasks can be difficult to get back into their sleeves when removed
• Opening on the women’s version flask is small, and the straw flops around some

Look around the starting line of almost any ultramarathon and you will see many runners wearing the Salomon Adv Skin 12 unisex running vest and Salomon Adv Skin 12 women’s running vest. And this is for good reason! This 12-liter vest was our testers’ hands-down favorite in the high-volume pack category and has topped the list of many other hydration pack reviews. It’s essentially a bigger version of the Salomon Adv Skin 5 hydration packs reviewed above, but bigger and with some modifications that make it the perfect pack for long days on the trail and self-supported adventures where you’ll be carrying your gear and nutrition for the entire day.

This pack features the same stretchy materials, elastic cord chest straps, mesh lining, and Sensifit construction as the five-liter version, so it can haul a serious amount of gear while maintaining a snug vest-like fit. The front pocket setup is also similar to the smaller version, with sleeves for two included 500-milliliter soft flasks, large stretch stuff pockets, and two zipper compartments to keep small items or your cell phone secure. Our testers found the flasks were a little tricky to get back into their sleeves on the unisex version compared to other packs with wider flask pockets.

A thermal sleeve for the bladder pocket can help keep water cool in the heat and keep it from freezing if you’re running in the cold. A vertical side zipper accesses the large rear main compartment and has impressive stretch to fit all the gear you need for a full day of running, and bungee compression cords on either side of the back help to stabilize the load. A smaller stuff pocket at the top of the pack can fit an emergency blanket or small jacket, and the pass-through tunnel pocket across the bottom of the rear compartment provides additional storage that is easily accessed on the go.

Unlike many other packs, this one is equally as comfortable to wear when it’s empty as when it’s stuffed full. This makes it a popular choice for ultra runners who want one pack that can do it all, whether they’re going out for a shorter training run or a long effort in the backcountry. There are multiple attachment options for carrying trekking poles on the front and rear, and a separate quiver can be attached. This pack is available in a unisex and a women’s version. The women’s version has lower flask pockets and flasks with long straws that sit below the chest.

To learn more, check out our in-depth Salomon Adv Skin 12 review.

Gear Capacity: 12 liters | Liquid Capacity: 2.5 liters | Hydration Carrying Method: Two 500-milliliter soft flasks (included), 1.5-liter hydration bladder (sold separately) | Model Options: Unisex and women’s-specific fit

Shop the Salomon Adv Skin 12 unisex running vestShop the Salomon Adv Skin 12 women’s running vest

Pros:

• Well built, durable, suitable for long days requiring a lot of gear and fluids
• Multiple zipper pockets for secure storage
• Excellent storage capacity

Cons:

• Heavy materials increase the pack weight
• Retains heat and runs warm
• Items bounce in front pockets if not full

The UltrAspire Zygos 5.0 Hydration Pack is a well-built 14-liter hydration pack for fully loaded all-day adventures or for a race that has an extensive required gear list. As with the UltrAspire Alpha 5.0 Race Vest reviewed above, this pack also features the brand’s ErgoFit harness that fits securely. We found that it is stable and comfortable, especially when the pack is full and heavy. The liner material of the pack features a soft mesh combined with thicker padded material at pressure points on the back and chest to optimize breathability and comfort. The pockets are made of reinforced nylon and Dyneema fabric, which results in them being durable yet stretchy for comfort and increased storage capacity.

The front of the vest has large stretch pockets that can fit 500-milliliter soft flasks or UltrAspire’s hybrid bottles. There are also additional zip and stretch compartments for food, maps, a cell phone, and any other smaller gear you want to have close at hand. These pockets are a bit loose, and our testers found that small items would bounce and shift if there were nothing else in the front pockets to stabilize them.

The side underarm pockets are large and stretchy, perfect for stashing gloves or a buff. One has a zip and magnet closure to keep the gear secure. The rear has a bladder sleeve with a removable insulated insert that holds the included two-liter hydration reservoir. A large zip pocket spans the back of the pack and has an excellent wide opening for gear access. It also has an inner small zip compartment with an attached key clip and an external stretch stuff pouch to stash an extra layer. There are two draw cords across the back to cinch down and compress the pack when loaded with water and gear, which can also be used to stow a jacket. The materials are thick and durable, but this, along with the black color, retained heat, and we found this pack to run warm — but not intolerably so.

The shock-cord MaxO2 Form closure system on the front of the pack is the only fit adjustment point. Elastic cords join together with two clips across the chest, and the closure is then tightened by pulling downward on the excess cord through a bungee locking mechanism. This pulls the cord tight, cinching the pack down across the chest.

This is easily undone by loosening the two bungee clips on either side to let out a little of the cord. Rear bungee loops across the low back of the pack hold trekking poles horizontally in place. We found this pack a little heavier than others but very sturdy and an excellent workhorse for long mountain days.

Gear Capacity: 14 liters | Liquid Capacity: 3 liters | Hydration Carrying Method: 2-liter bladder (included) and can fit two 500-milliliter soft flasks or UltrAspire hybrid bottles (not included) | Model Options: Unisex

Shop the UltrAspire Zygos 5.0 Hydration Pack

Other Top Hydration Packs for Running

Pros:

• Lightweight and breathable
• Very affordable, even with the extra cost of bottles or a hydration bladder
• Quality materials and good pocket setup

Cons:

• One-size-fits-most sizing may not accommodate all bodies
• Have to remove bottles or flasks to drink
• You have to remove the pack to access the rear storage

The UltrAspire Spry 3.0 Race Vest is a 3.5-liter capacity pack that offers excellent storage and features at a very affordable price. The materials are breathable and lightweight, and there are just enough pockets to hold your essentials for anything from a half marathon to a fast, well-supported ultra run. In addition to being our budget pick, this vest also rated very highly overall in the low-volume testing category.

Two front pockets are oriented lower on the chest and can hold hydration in a soft flask or the UltrAspire Ultraflask 550 hybrid bottles. These front pockets are also great for holding snacks and other small items. Our testers didn’t love that the flasks needed to be removed to drink but otherwise liked the front pocket arrangement. A single rear pocket can fit a one-liter bladder and includes a sweatproof liner, and the pack also has a smaller water-resistant zipper pocket and magnetic closure. An external elastic shock cord on the back can stash a jacket.

This vest utilizes the same ErgoFit harness with its elastic chest strap-and-hook closure as the above-reviewed UltrAspire Alpha 5.0 Race Vest, with simple webbing straps on the sides to adjust fit. Unlike most other packs on the market, this is a one-size-fits-most vest. According to UltrAspire’s size chart, it can fit a chest size range from 26 to 48 inches, accommodating a wide array of body types. No flasks or hydration bladder are included, which will add cost if you want them. Even with having to buy flasks or a bladder, this vest is still more affordable than most similar setups.

To learn more, read our UltrAspire Spry 3.0 Race Vest review.

Gear Capacity: 3.5 liters | Liquid Capacity: 2 liters | Hydration Carrying Method: Can fit two 500-milliliter flasks or hybrid bottles in the front and a 1-liter bladder in the rear pocket. No flasks or bladder are included in the vest purchase | Model Options: Unisex, one size fits most

Shop the UltrAspire Spry 3.0 Race Vest

Comparing the Best Hydration Packs for Running

Buyer’s Guide: How to Choose the Best Hydration Pack for Running

Pack Size

One of the main delineating features between the best running vests is size. Pack capacity is typically described in liters, much like a hiking or backpacking pack. Running hydration vests are much smaller than a traditional backpack and designed to be form-fitting and vest-like to minimize the pack bouncing around. The storage capacity of running packs is usually broken up into multiple pockets and compartments, which are split between the back and the front chest area instead of having one large rear pocket like a traditional backpack.

While many variables go into choosing the best hydration pack for running, a good rule of thumb is to select a pack size based on how long you will be out on the trails. For shorter runs of less than two hours or a race with frequent access to aid stations, a pack of two to five liters of capacity, like the Nathan Pinnacle 4 Liter Hydration Race Vest or the Nathan Pinnacle 4 Liter Women’s Hydration Race Vest, will be adequate to carry your hydration, food, and essentials. For those mid-range runs that are in the three- to six-hour range or in more challenging or slow-going terrain, one of the midsize six- to 11-liter packs, such as the USWE Pace 8L Trail Running Vest, will give you a little extra storage space for gear and liquid carrying capacity.

For all-day adventures or runs in more mountainous terrain where extra gear and layers will be required to guard against changing weather, a larger pack in the 12- to the 15-liter range, like the Salomon Adv Skin 12 unisex running vest and Salomon Adv Skin 12 women’s running vest, will be needed. If you are considering a race with a mandatory kit, this larger capacity is the best choice for stowing your rain jacket, layers, headlamp, and other essentials. Running-specific hydration packs max out in the 15-liter capacity range. If you are looking for a larger capacity pack for a longer or multi-day adventure, check out our best fastpacking packs guide, as these will better serve the needs of that type of run or hike.

Small hydration packs are great for carrying essentials on shorter runs. Photo: iRunFar/Eszter Horanyi

Fit and Adjustability

Once you decide on the right capacity, the most important consideration when choosing the best hydration pack for running is the fit. Running hydration packs are close-fitting, with a vest-like wraparound style that sits higher on your torso than a traditional backpack. This fit makes it easier to access storage on the go and keeps the pack close to your body to prevent it from shifting and moving around.

Most running vests are made of material that has some give so that it can move with you while you are twisting, running, or breathing. They typically have at least one point of adjustment — most often an adjustable chest strap that tightens and loosens the pack easily on the fly. The USWE Pace 8L Trail Running Vest has a unique front adjustment system that is simple to use, something to consider if you want to use the vest during long efforts where you’ll get tired or in the cold when your fingers may be cold. Some packs, like the Osprey Duro 1.5 or the Osprey Dyna 1.5, have two front adjustment straps, while other packs, including the Kailas Fuga Air II Trail Running Hydration Vest Pack 5L, have a single piece of cord for adjustment.

Some running vests have additional areas of adjustment on the sides or back of the pack to secure your gear and keep it from shifting around. These can range from a simple strap to a more complicated webbing or a Boa-adjustment system to really dial in the fit.

All hydration pack manufacturers have different sizing and fit, so it is important to review their brand-specific measurement and fit guides to be sure you are selecting the correct size and fit. The most important measurements for pack fitting are around the widest part of your chest and the bottom of your ribcage. Your best option for choosing the right-sized pack is to go into a running specialty store and try on a variety of options. There are also differences in preferences when it comes to pack sizing. Some people like their packs super snug, while others want a little breathing room.

When trying a pack on for the first time, you’ll find that you can get the best fit if you load a long run’s worth of essentials—or some volume resembling it—into it beforehand. Loosen all the straps completely, then tighten the sternum and side adjustments until they feel secure but not constrictive.

Maggie Guterl tests phone storage on a running hydration pack. Photo: iRunFar/Eszter Horanyi

Some packs offer a vertical sliding rail to adjust the position of the sternum straps, while others have a hook or “T” attachment with several fabric loops along the front to allow you to customize the fit by changing the position of the straps across your chest. This extra layer of adjustability across the chest allows runners of all shapes and sizes to use a pack. A hydration pack should fit snugly but not restrictively, and you should be able to twist your trunk, swing your arms, and breathe easily without the pack shifting or excessively bouncing.

Some packs come in a gender-specific fit, meaning anything from smaller sizes and colors to a completely different pocket and hydration-carrying configuration. It’s important to note that these changes don’t always translate to a better fit. For example, many of our testers, regardless of gender, prefer the fit of the Salomon Adv Skin 12 unisex running vest and Salomon Adv Skin 5 unisex running vest over the women-specific option. The takeaway here is to consider your body type and do a little research into the size ranges and existing reviews for the pack to help you choose the best hydration pack for running that fits your body type.

Breathability

When temperatures rise, a hydration vest allows you to carry the water you need on a run. Unfortunately, adding a hydration pack also adds extra material to your back and chest, which can increase heat retention and sweating. A pack’s breathability is crucial to mitigate this effect and keep you comfortable when running in the heat.

The factors that most impact the pack’s breathability are the inner mesh that contacts your body, the outer body material, and the amount of your back and chest the vest covers. All of the packs we tested have some type of lightweight mesh material lining next to the body, usually polyester, that is perforated or honeycombed to improve ventilation and moisture wicking. The heat retention of packs really differs in the rear pocket and outer pack materials.

Packs that scored very highly among testers for breathability, such as the UltrAspire Spry 3.0 Race Vest, UltrAspire Alpha 5.0 Race Vest, Kailas Fuga Air II Trail Running Hydration Vest Pack 5L, and USWE Pace 8L Trail Running Vest, all have a mesh lining and pockets that are made of lightweight stretchy materials to allow for good airflow. There are no water-resistant panels to retain moisture and heat, and any insulating panels are removable to improve breathability when you need it.

In contrast, some of our other top picks, such as the Salomon Adv Skin 5 unisex running vest, Salomon Adv Skin 12 unisex running vest, and the UltrAspire Zygos 5.0 Hydration Pack, have nylon panels or outer pocket materials that improve durability and moisture protection but increase heat retention. All of these are great packs that our testing team ranked very highly, but if you are routinely running in hot conditions or have a high sweat rate, the breathability factor will weigh more heavily than for those who run more frequently in cool, dry conditions.

iRunFar’s Meghan Hicks testing a hydration pack during a fall mountain run. Photo: iRunFar/Eszter Horanyi

Water-Carrying Capacity

The main point of a running hydration pack is, well, hydration! A handheld bottle or running belt can suffice for short runs and moderate temperatures, but when tackling hours on the trails, especially in hot, humid conditions, you’ll need more fluids to keep you going and an easy way to carry them.

The water capacity of running hydration packs varies significantly. Smaller packs, including the Salomon Adv Skin 5 unisex running vest and Salomon Adv Skin 5 women’s running vest, can typically hold around one liter of fluids, while larger packs meant for longer runs can hold three liters or more. Most hydration packs carry fluids in two ways: soft flasks in front pockets on the chest or in a hydration reservoir, commonly referred to as a bladder, that fits in a rear compartment on your back.

All but the smallest packs have both options. The debate between flasks and hydration bladders has no right or wrong. It simply comes down to comfort and personal preference.

The amount of water-carrying capacity you need in your pack should be determined by the type of terrain and conditions you most frequently encounter. A smaller capacity pack will do the trick for shorter runs or races with frequent aid stations. Easy access to water sources such as stream crossings can also lighten your load, as you can filter water along the way. You can check out our best water filters for trail running guide for some of our favorite water filters to carry out on the trails. For long days without easy access to water or in very hot weather, a larger pack that can fit at least a two-liter reservoir and two 500-milliliter flasks in front is the best choice.

Soft Flasks or Bladder

As mentioned above, running hydration packs generally have two ways to carry water: flasks or bottles and a hydration bladder. Choosing the best hydration pack for running comes down to weighing comfort, ease of gear access, and the water carrying capacity. Larger packs, like the UltrAspire Zygos 5.0 Hydration Pack, make it easy to carry a lot of water comfortably with a combination of flask and bladder storage options, and they can also carry extra layers, a first-aid kit, nutrition, and everything else you need for a big day out on the trails.

The technology behind the best hydration packs for running has changed dramatically, with the earliest versions being essentially a water bag inside a backpack. A bladder in the back of the pack is still a go-to for most hydration packs, especially those that cross the lines between sports such as cycling, hiking, and backcountry skiing, but many, for all sports, have switched to include front flasks as well.

Bladders are the easiest way to carry large amounts of liquid. Most packs can fit a two-liter bladder fairly easily. Using a bladder instead of soft flasks frees up front pockets for stashing essentials like nutrition and your phone in an easy-to-reach place. On the negative side, hydration bladders tend to slosh more if there is excess air in them and add extra weight to your back, which some runners don’t like. It is also more difficult to keep track of how much you are drinking with the bladder since it is out of sight. Refilling a bladder is also more cumbersome and time-consuming than soft flasks, something to consider if you’re racing.

While a few running vest options have a rear bottle holster, most running hydration packs use bottles or collapsible soft flasks in pockets on the front of the vest over the chest. The usual capacity of these is about 500 to 600 milliliters (20 ounces). Soft flasks give quick access to your fluids, making refilling easy without taking the pack off. They also make it much easier to mix and match your hydration needs with electrolyte drink mixes, plain water, or even soda (because sometimes ginger ale or Coke are the only things that work, am I right?)

On the downside, two 500-milliliter soft flasks will only give you one liter of liquid capacity. They also usually sit in front pockets over the chest, which may be uncomfortable for some runners, especially those with larger chests. The Osprey Duro 1.5 and the Osprey Dyna 1.5 are designed primarily to use a bladder but can also fit small soft flasks.

Testing trail running pole storage on the Salomon Adv Skin 12 unisex running vest in Colorado. This pack earned high honors in the large-capacity category of this guide. Photo: iRunFar/Eszter Horanyi

Pocket Placement and Storage

While hydration may be the primary function of your running pack, the gear-carrying ability of the best packs sets them ahead of the rest. Pocket size and placement are crucial to the organization and functionality of the pack. Easy access to essentials on the go and secure storage for extra gear and valuables are key features of our favorite packs. The UltrAspire Zygos 5.0 Hydration Pack has enough pockets to carry a huge array of items easily and securely.

The most common pocket arrangement for running hydration packs is a combination of smaller front pockets and larger rear compartments, with some packs utilizing the material under the arms for storage. The best pockets are stretchy enough to expand their capacity while being elastic enough to prevent sagging and bouncing in order to keep your gear secure.

Front pockets are found on pretty much all running hydration packs on the market today, and for good reason! Front pockets are usually separated into pockets designed to hold a soft flask and additional compartments overlying the soft flask pockets for storage. These make it super easy to stash and access frequently needed small items such as nutrition, lip balm, a cell phone, and more without removing your pack.

All but the smallest running hydration packs have at least one storage pocket on the back, usually a pouch spanning the length of the pack that holds a hydration bladder and also secures a jacket, extra layers, a first-aid kit, and other gear that does not need to be quickly accessible. Most running vests add additional storage capacity by adding stretchy overlay pockets onto the larger back compartment to provide extra room without adding excessive weight.

Hydration packs are available to suit any running needs. Photo: iRunFar/Kirsten Kortebein

Common rear storage and pocket arrangements include an inner sleeve inside a single large back pocket to separate it into two compartments, a top-loading or kangaroo-type tunnel pocket across the bottom for access to gear without removing the pack, an open stuff pocket on the outer part of the pack, or bungee cinch cord attached to the outer compartment. Our favorite packs feature some combination of these to maximize gear capacity without adding bulk.

In addition to the basic storage setup of the pack, there are a few extra details that are worth considering depending on your intended use of a pack. Secure closures, such as zippers, Velcro, or clasps, are an important consideration if you do a lot of bending, scrambling, or taking your pack on and off frequently to avoid inadvertently dropping or losing important gear.

A water-resistant pocket for valuables such as your key or cellphone may be an important addition in wet climates or all-day rainy ultras. Perhaps the most important pocket add-on detail is a key clip — because no one wants to return to their car or home to find their key dropped out of their pocket somewhere along the trail.

A hydration pack allows you to extend the range of your trail runs since you can carry liquids, snacks, and gear. Photo: iRunFar/Eszter Horanyi

Clasps and Closure System

The chest strap closure system of a pack is a small detail with a significant impact on fit and functionality. The best hydration packs for running use several methods for chest strap closures, but simplicity and ease of use are hands down the most important features of any system.

The most common chest strap closure is a simple buckle, similar to a traditional backpack sternum closure. These are easy to use and typically do not require much focus or dexterity, which is important for cold fingers and tired brains. There are also a variety of other unique systems on the market. In the case of the USWE Pace 8L Trail Running Vest, one single large buckle centered on the chest is about as simple as it gets! The Osprey Duro 1.5 and Kailas Fuga Air II Trail Running Hydration Vest Pack 5L employ a slightly different variation of the plastic buckle closure, with plastic clips attached to the sternum straps.

Another commonly used chest strap closure is a cord that stretches across the chest and attaches to a plastic hook. The strap is then adjusted by pulling the cord through a bungee clasp system to tighten and loosen it as needed. The Salomon Adv Skin 5 unisex running vest, Salomon Adv Skin 12 unisex running vest, UltrAspire Alpha 5.0 Race Vest, UltrAspire Zygos 5.0 Hydration Pack, and the UltrAspire Spry 3.0 Race Vest use some form of this closure. This system’s adjustability on the fly and ability to stretch with chest expansion while breathing set it apart from more traditional strap options. These closures require a bit more dexterity to align the strap over the hooks and thus can be tricky in very cold conditions or while wearing gloves.

Durability

Hydration packs are expensive and a significant investment for most runners. They should last a long time. A pack’s durability depends on the fabric type, clasps, and cords used in its construction, as well as your use and care.

A zipper, pocket, or clasp failure could range from minor inconvenience to catastrophe if it happens in remote terrain, so your intended use of the pack and the terrain you plan to run on should be factored into choosing the best pack for you. Someone whose runs take them to remote mountain ridges or bushwhacking through trees and rocky terrain will have different durability requirements for a pack than someone who mostly runs on gravel roads.

As with many other pieces of trail running and outdoor gear, when material weights decrease, durability also tends to decrease. Running hydration packs tread a fine line when it comes to minimizing the weight of the pack while maintaining the durability of the fabrics, straps, cinch cords, buckles, and clasps. All the packs we tested fared well in terms of their durability, with no significant tears or breakage in our testing period. Some packs, such as the Salomon Adv Skin 5 unisex running vest and Salomon Adv Skin 12 unisex running vest, have been used by our testers for years and years without any durability issues.

François D’Haene wins the Hardrock 100 with a relatively small hydration vest.

Extra Features of Running Hydration Packs

As discussed before, many thoughtful details have gone into the design and construction of the best hydration packs for running. In addition to the pocket layout, materials, and fit, several additional features enhance the safety and functionality of the pack.

• Whistle — Most of the best running vests today, including the Osprey Duro 1.5 and the Osprey Dyna 1.5, have a whistle that is most often attached to one of the front straps by a loop or cord. These tuck into an adjacent pocket to stay secure yet are easily accessible when needed in an emergency. This small and simple accessory can have a significant impact if you are lost or injured and need to summon help. Many races include a whistle as part of their mandatory kits.
• Trekking pole holders — Trekking poles have become a staple at mountain races and ultramarathons around the globe, and running hydration packs have a variety of ways to store poles when not in use, including front- and rear-mounted options. These are often elastic or bungee attachments that cinch poles in place, allowing easy access when needed. You can also add a quiver to the back of your pack.
• Cellphone pocket — Most people carry a phone with them while running, and most hydration packs have a pocket that fits even larger phones. In some cases, like on the Nathan Pinnacle 4 Liter Hydration Race Vest and the Nathan Pinnacle 4 Liter Women’s Hydration Race Vest, these pockets are water resistant, and other packs have pockets with a zipper or cinch cord to keep the phone secure.
• Attachments for ice axes or helmets — Ice axe loops or helmet attachments are uncommon among most smaller-capacity running-specific packs but may be an integral accessory for runners who frequent mountainous alpine terrain. These features are more frequently found on higher-capacity packs, like fastpacks.

Kyle Curtin testing a hydration pack on a run in Colorado. Photo: iRunFar/Eszter Horanyi

Why You Should Trust Us

For the initial version of this guide, our testing process began with extensive research into the running hydration packs and vests available today. After compiling a list of over 130 packs ranging from the small Osprey Duro 1.5 to the  UltrAspire Zygos 5.0 Hydration Pack, which will carry everything you need for a long day out, we narrowed it to 25 for intensive testing.

We spent several months piling water and gear into our packs and hitting the trails from humid U.S. East Coast ultramarathons to high-elevation mountain terrain in Colorado and everything in between. Our testers ran everything from dirt roads to rocky ridgelines, putting in fast, flat miles and slow-moving scrambling to find packs that performed well in all conditions.

We know that runners have various pack needs for different situations, so we tested options ranging from ones that would work well for urban runs or short races to those that could hold everything we’d need for big days in remote areas. Whether we had a pack out on a short recovery run or a long romp in the desert where we had it filled with as much water as it could carry, we were constantly assessing the wearability and functionality of the pack, especially whether or not we could get to everything we needed easily without having to take the pack off and dig through it. Our team assessed each pack’s fit, pocket layout, ease of use, comfort, style, weight, breathability, pole-carrying ability, and durability. We also considered the flasks and/or bladders they came with and any extra features. Testers took the packs in all weather conditions, from hot and dry to cold and rainy, and everything in between to see if we’d overheat or if the fabric got saggy when wet.

We continue to test new packs as they come on the market so that we can keep this guide updated and make it as easy as possible for you to find the right running pack for your specific needs.

Hydration packs come in all shapes and sizes. Photo: iRunFar/Bryon Powell

Frequently Asked Questions About the Best Hydration Packs for Running

When should I run with a hydration pack?

The temperature, terrain, and duration of your run, in addition to personal preference, will all play a role in answering this question. If you have to carry more gear than what will fit in your pockets or a running belt, it’s time to start considering a pack. This may be for an hour-long run in the heat or for a race that has a significant mandatory gear list. For shorter outings, a small pack, like the Osprey Duro 1.5 or the Osprey Dyna 1.5, can easily carry essentials and keep you from trying to stuff too many items into pockets. Carrying a pack is also an easy way to keep your hands free, which many of us prefer, even for short runs.

Runs in more remote locations or difficult terrain may require extra gear, like a first-aid kit, trekking poles, and extra layers. Any multi-hour adventure and almost all ultramarathon races will require a pack to carry the gear, food, and water needed for a safe and comfortable day on the trails.

What capacity hydration pack do I need?

This mainly depends on the type of running or racing you intend to do. The smaller capacity packs in the one- to five-liter range, including our favorites, the Salomon Adv Skin 5 unisex running vest and Salomon Adv Skin 5 women’s running vest, are perfect for shorter runs and races where minimal gear and hydration are needed, such as a two-hour run, a well-supported ultramarathon with frequent aid, or a two- to four-mile repeating loop course where you may not want a bottle in your hand the entire time but don’t need to carry hours worth of nutrition or gear.

A mid-capacity pack in the six- to 11-liter range will give you extra storage space for food, fluids, and layers to extend your unsupported running time. For all-day runs or high mountain adventures where you need to carry multiple extra layers and safety equipment, a high-capacity 12-plus-liter pack will be the way to go.

Don’t want to have a closet full of packs? Don’t worry! Most of the higher-capacity packs are made of lightweight, stretchy materials that are made to fit close to your body when not full, so if you need one pack to take you through both your two-hour training runs and your ultramarathon on race day, these will expand to fit gear and also wear comfortably when not stuffed to the gills. The Salomon Adv Skin 12 unisex running vest and Salomon Adv Skin 12 women’s running vest were our favorite of the larger capacity packs we tested.

How should my running hydration pack fit?

Your pack should fit snugly against your body and not shift or bounce with movement. Pack movement is both uncomfortable and can cause chafing. You will want enough room in the arms to have an unrestricted arm swing and enough space in the chest to tighten the sternum straps to secure the pack but not restrict breathing. Packs like the Kailas Fuga Air II Trail Running Hydration Vest Pack 5L have advanced adjustment systems to dial in the fit.

The best running hydration packs are made to sit high on the back and torso. All pack manufacturers included in this buyer’s guide have a size chart for their packs and instructions on taking proper measurements to ensure an accurate fit. That being said, some packs just fit bigger or smaller than expected, even when measurements are taken, so there is definitely some trial and error involved in finding your perfect fit.

We tested the storage pockets on several hydration packs to see what allows accessibility and organization for trail running the best. Here, Jeff Rome tries out the pockets on a Patagonia hydration pack. Photo: iRunFar/Eszter Horanyi

What should I carry in my running hydration pack?

While the name implies that hydration packs are mostly used to carry water, most runners use them to carry an array of items in addition to liquid. Once you square away your fluid carrying in soft flasks, bottles, or a bladder, you will want to consider the other items you want to have on hand while out on a run or race. Food, energy gels, and electrolyte powder are common items found stashed in packs.

Depending on the weather, a hat, gloves, buff, jacket, or extra layer may be in order. An emergency blanket and small first-aid kit are never a bad idea to have on hand. At the very least, some band-aids and tape will help in a pinch. A cell phone for safety, music, and photos is a must-have for most of us, and a small external charger for a phone may also make the cut for long days, especially if using a phone for navigation. The moral of the story is that hydration, food, and safety should always be at the top of your packing list. A pack like the UltrAspire Zygos 5.0 Hydration Pack will carry everything you need for a day in the mountains.

Is there a difference between men’s and women’s running hydration packs?

Sometimes. Several of the vests in this guide have both a unisex and women’s version, such as the Salomon Adv Skin 5 unisex running vest and Salomon Adv Skin 12 unisex running vest, which have different layouts and pocket configurations that change the fit of the vest. Other brands have men’s and women’s versions that have the same design but differ in colorways and sizing range. Many others have one unisex version.

The gender-specific designation typically doesn’t mean much in terms of the pack’s actual technical specifications and function — it simply changes the fit. We always recommend runners choose the layout, setup, sizing, or color that suits them the best, regardless of whether it is labeled men’s or women’s.

Racing hydration packs are lightweight and breathable. Photo: iRunFar/Meghan Hicks

Should I carry my liquids in bottles, soft flasks, or a hydration bladder?

This is very much a matter of personal preference and may take some experimenting to see which setup you prefer. For faster runs or races where quick aid station turnaround is important, a flask or bottle is much easier to remove, refill, and replace than a bladder. For hot days or long runs, a bladder may be preferable for its additional volume, or a combination of both can ensure you have adequate fluids. A pack like the UltrAspire Zygos 5.0 Hydration Pack can easily carry three liters of liquid between a bladder and soft flasks.

Beth Pascall wears a lightweight hydration vest during the Western States 100. Photo: iRunFar/Bryon Powell

What are the best hydration packs for larger chests?

Several packs have features designed to improve comfort over the chest area. Women-specific models of packs, like the Salomon Adv Skin 12 women’s running vest and Nathan Pinnacle 4 Liter Women’s Hydration Race Vest, often place the front soft flask pockets lower on the strap than on the unisex model to avoid compressing the chest. Many runners find front flasks uncomfortable over the chest and may find a better fit using only a rear hydration bladder.

The sternum strap configuration and shoulder strap shape are other factors that can affect comfort over larger chests. Sternum straps with adjustable positions and some stretch to the straps themselves will likely be more comfortable than a rigid or fixed-position strap, which may lead to increased pressure. While multiple packs have design elements to fit women’s bodies better, the most important factor to consider is what is most comfortable for you. A larger-sized unisex pack may be a better fit than one marketed as women’s specific for many people, so some trial and error and a good return policy may be in order.

We should note that in the testing round for this guide, we did not have any larger-chested runners to provide detailed feedback about this. As we complete future testing, specific pack recommendations for large-chested runners will be added to this guide.

Which hydration pack is best for cold-weather running?

Hydration packs often provide the added benefit of keeping the core warm when running in cold weather. The downside is that they can cause your back and chest to get sweaty, which is best avoided when running in cold weather. Some packs, like the UltrAspire Zygos 5.0 Hydration Pack, have an insulated pocket for a bladder to protect the water from the cold. Also, if you’re running in sub-freezing temperatures, you’ll want to ensure the water you’re carrying doesn’t freeze. Water can easily freeze in the nozzle and hose of a bladder, so you’ll want to blow any water in the hose back into the bladder when you’re done drinking.

What’s the best way to attach trekking poles to a hydration vest?

Unless you’re doing a race or a run that is straight up a hill, you’ll probably want a way to stow your trekking poles when not in use. There are several different styles of attachment systems for trekking poles on various packs, and it comes down to personal preference for which you prefer. A pack like the UltrAspire Alpha 5.0 Race Vest has an elastic cord on the bottom that allows you to attach poles horizontally across your lower pack. Other packs can attach the poles vertically along the front of the pack, which is a design that we don’t recommend due to the potential for injury if you fall. The  Salomon Adv Skin 12 unisex running vest and Salomon Adv Skin 12 women’s running vest have multiple pole attachment options, and many runners are choosing to attach a pole quiver to these packs to store their poles easily.

Call for Comments

• What is your favorite hydration pack for running?
• What types of runs do you use your hydration pack for?
• What running hydration pack feature is a must-have?

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