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Staying hydrated is important for any outdoor enthusiast, so hydration packs are essential if you’re in it for the long haul. In warm climates and the hot summer months, easy access to water is a must when you’re exerting yourself outdoors. Strenuous activity in the sun can quickly lead to dehydration, a surefire way to find yourself sitting out the next ride, run, or hike. But it isn’t easy to lug around jugs or bottles of water. Long-distance runners, hikers, cyclists, and other outdoor adventurers want to move around unencumbered, and that’s where the best hydration pack can come in. Hydration bags come in the form of backpacks or waist packs (like a fanny pack) that contain a reservoir for water storage, so you can strap your water supply to your body and get on the road or the trails. We tracked down five of the best hydration packs for outdoor athletes, so if you thirst for options, read on. 

How we chose the best hydration packs

Many of us at PopSci are bonafide Sporty Spices. We bike, hike, and maybe even ice skate. Some of us also use treadmill desks, under-desk bikes, standing desks, walking pads, and more to keep moving while working. And we’ve spent time with plenty of smart home gym equipment. With all that gear at hand, we personally tested hydration packs while also asking experts and looking at reviews and recommendations to separate the leaders of the (hydration) pack from their dry opponents.

The best hydration packs: Reviews & Recommendations

Hydration backpacks come in different styles tailored to running, hiking, or biking/cycling. One of our choices should help you stay hydrated on your next adventure—don’t be afraid to leave that insulated water bottle in the car.

Best overall: Osprey Raptor 10 Bike Hydration Bike Backpack




  • Bladder size: 2.5 liters
  • Sport: Biking
  • Weight: 1.6 lbs.
  • Backpack size: 10 liters


  • Lots of extra features like hip pockets and helmet attachment
  • Can also be used as a day pack
  • Large bladder size


  • Bag is not waterproof and doesn’t include a rain cover

Designed as a bike pack, the Osprey Raptor 10 Bike Hydration Backpack includes a 2.5-liter hydration bag and can also be used as a day-hiking backpack. Even weight distribution, hip belts, the LidLock helmet attachment, and a sleek look make the Osprey Raptor our pick for the top hydration pack.

Best for hikers: CamelBak Fourteener 26 Hydration Pack




  • Bladder size: 3 liters
  • Sport: Hiking
  • Weight: 2.3 lbs.
  • Backpack size: 26 liters


  • Large bladder and backpack capacity
  • Lots of back support
  • Overflow pocket to store an extra layer or other stashables


  • Expensive

The CamelBak Fourteener 26 Hydration Pack is designed for long hikes on hot days. Its reservoir holds 3 liters of water, and it’s designed with dual wing belts and an inner cargo belt to take the weight off your shoulders. More than a hydration backpack, the Fourteener also boasts 23 liters of cargo capacity for snacks, sunscreen, and other important hiking gear.

Best for bikers/cyclists: Thule Vital Hydration Pack




  • Bladder size: 2.5 liters
  • Sport: Biking
  • Weight: 1.15 lbs.
  • Backpack size: 6 liters


  • Retrakt magnetic hose system
  • Large enough to carry a bike pump and repair kit
  • Low center of gravity


  • Chest strap sits high depending on body type

The hands-free design of the Thule Vital 6 Hydration Pack is perfect for bikers and cyclists who need to hydrate mid-ride. Thule’s Retrakt magnetic hose system automatically returns the drinking hose to its place after each sip, so riders always know where to find it. Bikers and cyclists can carry up to 2.5 liters of water and 6 liters of additional storage for a pump and repair kit.

Best for runners: TETON Sports Trailrunner 2.0 Hydration Pack

ETON Sports



  • Bladder size: 2 liters
  • Sport: Running
  • Weight: .9 lbs
  • Backpack size: 2liters


  • Low-profile design
  • Lightweight and sturdy
  • External pocket for items that need to be within reach


  • Can chafe parts of your body if not covered by clothing

Runners love the lightweight TETON Sports Trailrunner 2.0 Hydration Pack because of its secure fit. Straps and shoulder pads adjust to fit your body, preventing uncomfortable jostling during your run. The Trailrunner also comes with a free 2-liter bladder, and its intake hole is wide enough for ice cubes—perfect for keeping cool on a summer run.

Best budget: Water Buffalo Hydration Pack

Water Buffalo



  • Bladder size: 2 liters
  • Sport: Hiking, running, cycling
  • Weight: 7 ounces
  • Backpack size: 12 liters


  • Extremely lightweight
  • Splashproof nylon
  • Multi-purpose


  • No seal between twist cap and bag on bladder

The Water Buffalo Hydration Pack holds up to 2 liters of water and has several pockets for storing other essential items so that it can be used for a run, a bike ride, or even as a small hiking backpack. Its Oasis Hydration bladder is designed to keep water fresh and clean while also preventing pesky leaks. With fully adjustable straps, splashproof nylon, and ultralight material, the Water Buffalo will keep you hydrated even if you’re on a tight budget.

What to consider when buying the best hydration packs

There are plenty of designs available for different sports, so you can choose the best hydration pack depending on the type of activity in which you’re participating. Packs come in two main designs. The first is the waist pack, which belts around the waist and has slots for one or more water bottles. The other is the hydration backpack, which straps to your back and contains a reservoir, or water bladder. The bladder is connected to a long straw, so you can sip from the pack without taking it off your back.

Hydration backpacks typically hold more than waist packs. A standard water bottle holds roughly 0.5 liters of water, so that’s about the capacity you can expect from a waist pack. Backpacks come in different capacities, ranging from 0.5 liters to 3 liters of water. Stocking up on as much water as possible might seem like a great idea for a long bike ride on a sweltering day, but don’t forget all that water comes with extra weight—one liter of water weighs over 2 pounds. Water weight is just one of the considerations when searching for the best hydration pack.

Which activity will you be using the hydration bag for?

The first thing to consider when shopping for a hydration bag is that most are tailored to a specific activity. Hiking hydration backpacks are usually bulkier and provide more space for storage. Biking/cycling hydration packs tend to offer features for hands-free drinking. Running hydration packs are thinner and lightweight and often come as a vest. While many hydration bags are adequate for cross-training, they tend to lean toward one sport or another, so bear that in mind.

How much water do you want to carry in your hydration bladder?

Water weight is an important consideration when choosing the best hydration pack for you. A seasoned hiker going for a day-long climb might do best with a larger, 3-liter hydration bladder. A marathon runner, on the other hand, might prefer a less cumbersome waist pack that holds a single bottle the runner can sip from between water stations (where they can also refill).

What other features do you want in an outdoor backpack?

Before making a purchase, consider what extra features the outdoor backpack offers. Some hydration backpacks come with similar features to daypacks, with extra pockets and loops for storage. This is optimal for carrying snacks on long treks when you’ll need to fuel up along the way. Other features of the outdoor gear may include shut-off bite valves to prevent leaks, disconnecting tubes to simplify refills, and multiple portals for easy straw placement.

How comfortable is the day pack for you to carry?

Finally, make sure you feel comfortable carrying the day pack. If possible, try it on to ensure the hydration backpack fits properly on your body. Give it a test run while you’re biking, running, or hiking—something comfortable while you’re standing still doesn’t always feel so great when it’s jostling around during a run. Check that the backpack has a hip belt (most do) to relieve pressure on your shoulders. 


Q: How much does a hydration pack cost?

Depending on size and features, a hydration pack can cost between $25-$200.

Q: What hydration bag does the military use?

Although there is no one official hydration pack that the military uses, CamelBak prides itself on being a favorite among the armed forces. CamelBak offers a line of gear suitable for military use to keep forces hydrated and has even worked with the military to research turning the CamelBak design into a backpack that could hold oxygen. If you’re looking for a military-grade hydration bag, a CamelBak backpack is a top choice.

Q: How big of a hydration bladder do I need?

How thirsty are you? In all seriousness, how big of a hydration bladder you need depends on the activity you’re doing, how long you’re active, and other factors (including the color of your urine). CamelBak provides a hydration calculator to analyze these factors and determine the water necessary to keep you at peak hydration. Remember to drink water throughout the day and use a hydration bladder to supplement the fluids lost during exertion.

Q: Is a hydration pack worth it?

Staying hydrated is one of the most important things you can do for your body, and it’s often the most overlooked. A hydration pack is absolutely worth it to keep a water source close by during physical activities. There’s no better way to stay hydrated and cool on a long run, hike, or bike ride. In addition, many hydration backpacks provide more than just hydration—most come with additional storage space where you can organize tools, repair kits, phone, credit cards, sunscreen, a packable rain jacket, and other essentials for easy access. If you’re unsure if you need a hydration bag, start with a budget option and see how it suits you. Then you can decide whether to invest in a higher-end hydration pack. 

Final thoughts on the best hydration packs

One of the best ways to keep your body going during strenuous activity is to keep it hydrated! Athletes who ignore their water intake may begin to experience symptoms of dehydration, which include feeling fatigued, dizzy, and light-headed. Making hydration part of your fitness routine will help you run faster, bike farther, or enjoy a longer hike on a sunny day. There’s no excuse for being thirsty when you’ve got the best hydration pack, tailored for a specific sport, as part of your outdoor gear. Choose one that’s right for you, get out there on the trails, and don’t forget to drink up as you drink it all in!

Why trust us

Popular Science started writing about technology more than 150 years ago. There was no such thing as “gadget writing” when we published our first issue in 1872, but if there was, our mission to demystify the world of innovation for everyday readers means we would have been all over it. Here in the present, PopSci is fully committed to helping readers navigate the increasingly intimidating array of devices on the market right now.

Our writers and editors have combined decades of experience covering and reviewing consumer electronics. We each have our own obsessive specialties—from high-end audio to video games to cameras and beyond—but when we’re reviewing devices outside of our immediate wheelhouses, we do our best to seek out trustworthy voices and opinions to help guide people to the very best recommendations. We know we don’t know everything, but we’re excited to live through the analysis paralysis that internet shopping can spur so readers don’t have to.