Best Water Bottles for Running in 2025

The right water bottle for your run can ensure you stay adequately hydrated. Photo: iRunFar/Eszter Horanyi

Hydration is an integral part of life, and having a good water bottle can help you get enough fluids throughout the day. Choosing the best water bottle for running can allow you to carry the right amount of hydration in a way that works for you.

Sports performance experts say that for runs lasting longer than 60 minutes, bringing hydration is necessary if you want to feel your best. There are countless options, from hard-sided bottles that fit in a pack and can do double-duty in a gym bag to soft flasks in a handheld system; there’s something for every need. 

To narrow down the list of the best, iRunFar testers spent months filling, carrying, and drinking from various water bottles. We evaluated bottles based on ergonomics, ease of use, weight and size, functionality, and durability. Whether you’re looking for a squeezable flask or an indestructible insulated bottle, we’ve got you covered.

Among handheld water bottles, the Osprey Duro/Dyna Handheld, which easily carries a soft flask, is our top pick. The Hydrapak UltraFlask Speed 500ml is our favorite soft flask for carrying in a vest, and the insulated Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series is our first choice for everyday hydration or when we wanted to keep liquids cold or hot.

For more background information, see our buying advice, testing methodology, and frequently asked questions below the picks.

Best Water Bottles for Runners

Best Soft Flask Handheld Water Bottle: Osprey Duro/Dyna Handheld
Best Handheld Water Bottle: Amphipod Hydraform Jett-Lite Thermal Handheld 20 oz
Best Multi-Use Water Bottle: UltrAspire UltraFlask 550 Hybrid Bottle
Best Soft Flask: Hydrapak UltraFlask Speed 500ml
Best Insulated Plastic Water Bottle: Tracksmith Insulated Water Bottle
Best Daily Use Insulated Water Bottle: Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series
Best Daily Use Plastic Water Bottle: Yeti Yonder 1 L / 34 oz. Water Bottle
Best Water Filter: Katadyn BeFree Water Filtration System 0.6L

Hard-sided water bottles are great for road interval sessions and everyday use. Photo: iRunFar/Eszter Horanyi

Best Soft Flask Handheld Water Bottle: Osprey Duro/Dyna Handheld ($40)

Pros:

• Comfortable hand strap

Cons:

• Small pocket with minimal stretch

When you want to go for a quick run and need an easy water bottle to grab on your way out the door, the Osprey Duro/Dyna Handheld is a great option. The stabilizing jacket holds a 360-milliliter (12-ounce) soft flask and wraps comfortably around your hand. The flask is just the right size for shorter runs when you just need something to sip on or for longer runs when you pass by water fountains or other water sources that you can use to fill up as you go.

We found that the jacket also easily held larger flasks, especially shorter and wider ones, though long and skinny flasks worked fine, too. The flask jacket, made entirely from recycled materials, has a convenient mesh zippered pocket for carrying essentials like keys or a gel.

It features a PFAS-free durable water repellent (DWR) coating, so it doesn’t immediately soak up water if you get caught in the rain. The jacket’s ambidextrous design allows you to wear it with either hand to switch it up throughout your run. Finally, there’s a safety whistle on the pocket zipper, which you can use to attract attention if needed.

Best Handheld Water Bottle: Amphipod Hydraform Jett-Lite Thermal Handheld 20 oz. ($39)

Pros:

• Comfortable ergonomic bottle

Cons:

• A relatively large bottle that may not be comfortable for runners with smaller hands

The Amphipod Hydraform Jett-Lite Thermal Handheld 20 oz. is an excellent option if you want a handheld system that carries a hybrid bottle instead of a soft flask. The hand strap connects to a thermal sleeve that securely holds the included 20-ounce water bottle and keeps liquids cool, although removing the neoprene insulation is easy if you don’t need it.

Although the 20-ounce volume is bigger than most other handheld bottles, given the structure of the carrying system, we didn’t feel it was cumbersome to carry. A 12-ounce option is also available if you don’t need to carry that much water. The strap’s cushioning is comfortable around the hand and easily adjustable for any hand size.

We found the entire system incredibly secure. With several different strap configurations, we didn’t have any issues with the fit and feel of the setup, nor did it slip around. A small zippered pocket on the outside of the hand strap balances the water bottle’s weight and provides secure storage for small items. While the pocket isn’t big enough for a phone, it can easily hold keys and a gel.

Three different color options are available, and all the bottles are dishwasher-safe. This is an important feature if you like to carry drink mixes when running and need to clean them thoroughly afterward.

Best Multi-Use Water Bottle: UltrAspire UltraFlask 550 Hybrid Bottle ($15)

Pros:

• Hybrid material captures the benefits of both soft and hard flasks
• Great value

Cons:

• Not dishwasher safe
• Narrow bottle opening

When it comes to versatility, the UltrAspire UltraFlask 550 Hybrid Bottle stands out from the rest. While it may not look that much different from other bottles at first glance, the unique material has many of the performance features of a soft flask while still being a hard-sided water bottle.

It’s softer than most hard water bottles, making it easy to squeeze when you want to drink. It’s also comfortable to wear in various configurations, such as a vest or a belt. We liked how our vest pockets held their shape when carrying these bottles and improved the fit, but we did find that it was harder to get all of the liquid out of this type of flask without taking it out of the pocket compared to a traditional soft flask.

UltrAspire designed it to fit into its hydration packs, including the UltrAspire Zygos 5.0 Hydration Pack, featured in our best running vests guide. It also fits the UltrAspire Speedgoat 3.0 Waist Belt, which we feature in our best running belts guide. Because it is wider, it doesn’t fit in the pockets of all traditional running vests, especially ones designed to carry tall and narrow flasks.

We also loved this bottle for tossing it into a gym bag. The large valve makes it easy to gulp liquid if you’re thirsty and in a hurry. One downside, which is quite common across a range of water bottles, is that the opening of the actual flask was slightly too narrow to get ice into it. We also struggled to get powdered drink mixes into the flask without causing a mess.

Best Soft Flask: Hydrapak UltraFlask Speed 500ml ($23)

Pros:

• Lightweight, convenient SpeedFill cap

Cons: 

• The narrow design doesn’t fit all hydration packs

Hydrapak makes a large percentage of soft flasks used in the running world, and the Hydrapak UltraFlask Speed 500ml is one of our favorites. Weighing just over an ounce, this flask is easy to carry and squishes down to seemingly nothing when empty. Depending on the type of vest you’re using or your preference, you can use this flask with or without a long straw. The high-flow valve is easy to drink from and seals after each use, so you don’t drip water everywhere. The valve easily squeezes with your fingers to release excess air and minimize sloshing water.

New to this flask is the SpeedFill cap. Now, instead of unscrewing a bottle top at an aid station, you can flip it open to fill up on water. While this may seem like a trivial amount of time and energy saved, it can add up over the course of a long race. And with a 42-millimeter opening, getting drink powders and ice into this flask is easy.

This flask also comes in a 600-milliliter option that is a bit wider than the 500-milliliter one. We found that the 500-milliliter option was a bit narrow for many running vests and would bounce around, especially if it wasn’t completely full.

Best Insulated Plastic Water Bottle: Tracksmith Insulated Water Bottle ($20)

Pros:

• Keeps liquids cool
• Works on a bike

Cons:

• Not the best while running
• Shouldn’t be used with hot liquids

If you want to add an insulated bottle to your rotation, we strongly recommend the Tracksmith Insulated Water Bottle. Made by CamelBak, a leader in the water bottle industry, this 21-ounce double-walled bottle kept our water and electrolyte mixes cold for long periods. The squeezable bottle has a self-sealing cap that we found easy to use without liquids leaking or shooting everywhere. Those of us who have a habit of not closing water bottle lids appreciated this feature.

Although this bottle is more akin to a traditional cycling water bottle, and we don’t see it as something to carry during a run, it’s ideal for keeping on hand during track or interval workouts when you’re staying close to the same spot or as a post-run bottle to keep in your car. It’s convenient on hot days when your car heats up significantly.

Best Daily Use Insulated Water Bottle: Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series ($50)

Pros:

• Ice cubes for days (literally)

Cons:

• High price point

The rise of the insulated metal water bottle in recent years has been meteoric, and the Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series comes from a brand that led the charge. Known for its highly insulated bottles that can keep water cold and coffee and tea piping hot for seemingly forever, Hydro Flask has reduced the weight of this bottle by 25% without compromising its performance. While this isn’t a bottle to take out on a run, it’s perfect for everything else. The double-walled vacuum insulation keeps liquids hot or cold, and we found that it can keep ice frozen for many hours, even if left in the hot sun.

The bottle features stainless steel, which many people prefer for their drinking containers instead of plastic. The steel preserves the flavor of the liquid, and you don’t have to worry about plastic potentially melting if you want to carry around a scalding hot drink.

It is also impressively durable and can survive drops and other wear and tear from everyday use. Many of our testers have used Hydro Flask bottles for years and only replace them if they get lost. There are several different lid options for this bottle, and you can mix and match them depending on whether you’re looking for drinking convenience with a straw or a screw-on top that will remain sealed wherever or however you transport the bottle.

Best Daily Use Plastic Water Bottle: Yeti Yonder 1 L / 34 oz. Water Bottle ($28)

Pros:

• Dishwasher safe

Cons:

• Heavier than similar bottles on the market

The Yeti Yonder 1 L / 34 oz. Water Bottle is a simple and affordable everyday water bottle with various unique features. The BPA-free plastic is dishwasher safe, and as part of its commitment to sustainability, Yeti has made this bottle out of 50% recycled materials.

While it’s slightly heavier than other water bottles with a similar style, we noted that it felt pretty indestructible. It’s narrower and taller than many other bottle options on the market, and a flat spot on the side makes it comfortable to carry. Our testers with smaller hands especially appreciated this. This bottle comes in many sizes and colors, so you can choose the one that fits your water-carrying needs and stylistic preferences.

The two-part cap system sets this bottle apart from others on the market. The leakproof cap design screws off the bottle completely to make it easy to fill with water, and a smaller cap unscrews from the top providing a smaller opening for drinking. A smaller drinking hole helps minimize splashes and spills while drinking, especially if you’re drinking while moving.

Best Water Filter: Katadyn BeFree Water Filtration System 0.6L ($40)

Pros:

• Lightweight, compact

Cons:

• The filter will clog over time

While there are an increasing number of water filters that attach to a soft flask on the market, the Katadyn BeFree Water Filtration System 0.6L was the first, and it still holds its place as our favorite. Available in both 0.6-liter and 1.0-liter options, you can use the smaller version of this filter and bottle as a soft-flask replacement in a running vest or the larger one as a bottle you carry in a backpack or rear sleeve on a vest.

This lightweight filter is easy to use and can filter up to two liters per minute when new. The 0.1-micropore size removes bacteria, cysts, and other sediments from the water, making it easy to drink wild water when running.

We have used this water filtration and soft flask system for years and rely on it for everything from daily mountain runs to multiday fastpacking trips. The Hydrapak soft flask is durable enough for extended use, and the setup only weighs 63 grams. The filter does clog after extended use, but Katadyn sells it separately so that you can continue to use the flask for a long time.

Over the years, we have inserted pinprick holes into this flask, but we don’t believe these occur more frequently for this flask than for any other soft flask, especially given that we use this option for many backcountry trips in rugged environments.

This filter system tops our list in our best water filters for trail running guide. You can read more in our in-depth Katadyn BeFree review.

Comparing the Best Water Bottles for Running

Hydro Flask bottles have been a go-to water bottle for the iRunFar testing team for years. Photo: iRunFar/Eszter Horanyi

Buyer’s Guide: How to Choose the Best Water Bottle for Running

Types of Water Bottles to Use While Running

The best running water bottles generally fall into two categories: traditional hard-sided plastic bottles or soft flasks. There’s a newer option as well, hybrid bottles like the UltrAspire UltraFlask 550 Hybrid Bottle, which combines features of both. Each type has pros and cons, and the best choice for you ultimately comes down to your personal preference.

Hard-sided bottles such as the Amphipod Hydraform Jett-Lite Thermal Handheld 20 oz. or the Tracksmith Insulated Water Bottle maintain their shape and provide some insulation but can feel heavy and cause hand fatigue during a run. Moreover, sloshing water in half-full hard-sided bottles can also drive some people crazy.

Soft flasks like the Hydrapak UltraFlask Speed 500ml or the Osprey Duro/Dyna Handheld shrink down as they empty, making them small to store away, but this can also cause them to flop around or sink into their carrying sleeve or a hydration vest pocket when they are only partially full. In addition, the typical soft flask won’t insulate as well as a hard-sided bottle, especially if you’re carrying it directly in your hand on a hot day, although a carry system with a strap can help reduce this.

Both types of bottles can work in a pack or waist belt, and many are compatible with a strap that allows you to carry the bottle in your hand easily while running. Various flasks, bottles, and hand straps are interchangeable, and Hydrapak soft flasks appear in several handhelds, including the Osprey Duro/Dyna Handheld.

Additionally, many brands utilize the same flasks or bottles across different types of products. For instance, the UltrAspire UltraFlask 550 Hybrid Bottle is compatible with multiple handheld straps, waist belts, and packs across the brand’s product lines.

Heather Jackson runs the early miles of the 2024 Western States 100 with two extendable straws on her soft flask water bottles. Photo: iRunFar/Eszter Horanyi

Handheld Bottles Versus Hydration Bladders 

The typical duration, temperature, and terrain of your run, combined with your personal sweat rate and hydration needs, will determine how much you need to drink and which fluid-carrying method is best for you. That said, there is no right or wrong answer to the question of what the best running water bottle on the market is. Like many of us, you will probably use a few different bottles for different types of runs.

Running while holding a water bottle can take some getting used to, so our testers paid close attention to the weight and ergonomic feel of all the bottles we tested. A lightweight handheld bottle or soft flask paired with a sleeve like the Osprey Duro/Dyna Handheld makes it easy to carry 12 to 24 ounces of hydration, which is usually enough for shorter runs in moderately warm temperatures.

A running belt or hydration vest is usually the preferred method for carrying the necessary fluids, nutrition, and gear for longer runs. Check out our best running vests and best running belts guides to learn about available options.

Notably, most hydration packs have designs that accommodate bottles and a hydration bladder. Additionally, you can often use the same bottle with a handheld carrying system and in a hydration pack pocket.

Finally, for runners who are especially sensitive to the sound of their fluids sloshing with every step, a soft flask, like the Hydrapak UltraFlask Speed 500ml, is better than a hard-sided bottle, or a hybrid bottle like the UltrAspire UltraFlask 550 Hybrid Bottle, as it is much easier to remove excess air and reduce noise.

Water Bottles for Hiking and General Use

The most significant factors in choosing a bottle for everyday use, travel, and hiking are its capacity, weight, and durability. While a lightweight and ergonomic soft flask or collapsible bottle is an excellent choice for running, a more structured hard-sided bottle, such as the Yeti Yonder 1 L / 34 oz. Water Bottle, is better equipped to handle the wear and tear of daily use.

Most hiking and daily-use bottles feature materials like metal or plastic. They can withstand transport hazards, such as being dropped on the trail or tossed into the back of the car during a gear shuffle, without leaking.

A versatile, lightweight option that works in almost any setting, including running if needed, is a squeezable pull-top cap bottle like the Tracksmith Insulated Water Bottle. This cycling bottle is lightweight and easy to transport for work or travel. It will fit into your bike’s water bottle cage and the bottle sleeve pocket of a backpack.

A more robust and durable option for everyday use is a stainless steel insulated bottle, like the Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series. These come in many colors, sizes, and cap options and work with hot or cold liquids. They’re perfect for hiking in 90-degree weather in August and snowshoeing in January. They have excellent insulating capabilities and keep post-run ice water cold in your car, even during multi-hour hot-weather runs.

Hydro Flask bottles are a great insulated option for everyday hydration. Photo: iRunFar/Eszter Horanyi

Insulated Bottles

Insulated bottles are great for use in more extreme environments. It’s simply not refreshing to take a giant gulp of warm water during hot activities. An insulated bottle can prevent your ice water from turning to bathwater as the miles on trail add up.

With some vacuum-insulated metal water bottles, we’ve still had ice cubes intact after hours in hot weather, which is a huge plus when it’s toasty out there. A lightly insulated bottle like the Tracksmith Insulated Water Bottle won’t keep your liquids cold forever, but they can make a big difference as the hot hours add up.

Conversely, anyone who logs long hours in the cold risks freezing their hydration if it is not adequately protected and insulated. Tucking your bottle against your body or wrapping it in extra clothing in a pack helps some, but having a well-insulated bottle, like the Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series, is a great way to keep your liquid as a liquid instead of a block of ice. These insulated bottles are also great for transporting a post-run treat like soup or hot chocolate.

Materials, Weight, and Durability

Water bottles for athletic activities generally include plastic or stainless steel. These materials are durable, lightweight, and can withstand the drops and dings of adventure travel or midnight aid stations.

The lightest water bottle options are soft flasks, which generally feature thermoplastic polyurethane (TPU) or silicone. These materials make for lightweight and compressible bottles that work in handhelds, hydration packs, or waist belts. They’re also an excellent option for backup liquid capacity, as you can toss them into the back of a pack without adding significant weight and fill them during a run for longer stretches without water access.

Hard-sided plastic water bottles, like the Yeti Yonder 1 L / 34 oz. Water Bottle, are rigid with a cap and can’t be squeezed to get water out, while hybrid bottles, like the Tracksmith Insulated Water Bottle and the UltrAspire UltraFlask 550 Hybrid Bottle, have nozzle lids and can be squeezed to force the water out. These lightweight options can easily transition between hiking trails or a travel day.

Flexible bottles can also be used with many types of hydration packs, as they are easier to get in and out of pockets than a more traditional hard-sided bottle. Look for BPA-free options (all of our winning bottles are) to avoid exposure to harmful chemicals. However, we don’t recommend putting hot liquids in plastic bottles, even if they are BPA-free.

Stainless steel water bottles are a bit heavier but highly durable and virtually breakproof. If dropped enough, they will sustain their share of dents and dings. Our favorite stainless steel bottle, the Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series, features food-grade stainless steel, which resists odors well and is easy to clean. The vacuum-sealed insulation keeps hot and cold beverages at their intended temperatures, making these bottles great for year-round travel and outdoor adventures.

In addition to these options, glass and aluminum bottles are also on the market. Glass is the lowest risk regarding chemical leaching and taste or odor transfer, but it’s easy to break, making it less than ideal for running and active pursuits. Plus, it’s heavy. Aluminum is more apt to react to certain liquids and can corrode, so we would recommend food-grade stainless steel options over aluminum if you prefer a metal bottle.

Handheld Bottles, Running Vests, or Running Belts

A handheld bottle, such as the Osprey Duro/Dyna Handheld or the Amphipod Hydraform Jett-Lite Thermal Handheld 20 oz., is by far the simplest and easiest way to carry running hydration, and many people turn to handheld systems for the majority of their runs. A variety of bottle sizes, materials, and strap variations make for a comfortable and convenient way to carry smaller amounts of fluids that are easily accessible.

Most handheld bottles hold around 20 ounces, which is adequate for shorter runs or well-supported races that allow frequent bottle refills. If you use a bladder in a hydration vest as your primary liquid source, a handheld is also a great way to carry extra water, a different fuel, or an electrolyte mix.

You’ll probably need a hydration pack for long runs in more remote terrain to carry adequate fluids, food, and extra gear required for weather changes, safety, and first aid. Runners with wrist or hand problems may also prefer a hydration pack with a bladder or soft flasks over a handheld carry system, regardless of the duration or conditions of the run. Running belts are also a great option if you don’t need to carry much water but still want your hands free.

Most running belts will hold at least a 500-milliliter bottle. Photo: iRunFar/Eszter Horanyi

Different Caps for Running and Hiking Bottles

The simplest type of cap is a solid screw-on cap, which many hiking and everyday bottles utilize. These are leakproof and often have an attached carrying strap for easy transport. The Yeti Yonder 1 L / 34 oz. Water Bottle has a unique two-cap system that makes it easy to fill through a large opening and a smaller opening for easy drinking.

Soft flasks, like the Hydrapak UltraFlask Speed 500ml, usually feature a bite valve that only dispenses fluids when compressed, usually by biting down on it while drinking. These do not have an additional cap or closure system for simplicity and ease of use. And, you can accidentally spill your water by squeezing the valve when accessing other items in your pack or taking the flask in and out of its pocket. We suspect that most runners have accidentally emptied a soft flask in their car by accidentally putting a heavy item on its nozzle.

Why You Should Trust Us

We started this guide by researching available options for the best running water bottles and bottles for everyday use. From a list of nearly 100 options, we chose our top contenders for flasks, plastic bottles, handhelds, and insulated stainless steel bottles to put to the test. We hit the roads and trails with handheld bottles and flasks to find the best combination for hydration on the move.

We also tested multiple insulated metal bottles with hot and cold fluids to determine the most effective. In addition, our team of testers used hard-sided plastic bottles at work, at the gym, on hikes, and on long travel days in and out of airports and rental cars to determine which bottles hit the mark for weight, capacity, performance, durability, and cost.

Frequently Asked Questions about Water Bottles for Running

What kind of bottle or soft flask is best for running?

As mentioned above, there are numerous factors to consider when choosing between the best running water bottles, and ultimately, it comes down to personal preference, hydration needs, and comfort.

Soft flasks, like the Hydrapak UltraFlask Speed 500ml, are an excellent choice for use in both handhelds and packs, and they come in several different sizes. Soft flasks are a great and quiet choice for those who hate water sloshing around in hard-sided bottles and hydration bladders. They are also lighter and can collapse when empty, making them easier to hold and stash away when not in use. Many of the most popular running soft flasks, including the flask on the Katadyn BeFree Water Filtration 0.6L, are made by Hydrapak.

Plastic squeezable water bottles are another great choice and come in various shapes and fluid capacities. In addition to the typical cylindrical shape, which is ideal for someone who also wants to use their bottle on a bicycle, there are multiple options for ergonomically shaped bottles that are more comfortable to hold and reduce hand fatigue — our favorite is the Amphipod Hydraform Jett-Lite Thermal Handheld 20 oz. Multiple cap options with locking mechanisms and valves make the bottles on the market today easy to drink from and secure when not in use, avoiding leaks and spills on the run and in your bag or car.

Alli Miles of iRunFar uses the Hydrapak UltraFlask Speed 500ml during a road run. Photo: iRunFar/Eszter Horanyi

What size bottle is best for running?

Various factors will determine the best-sized bottle for your needs. Distance, weather, temperature, sweat rate, and access to refill opportunities are all important considerations when gearing up for your run.

For shorter runs of an hour or less, running in cooler temperatures, or outings with frequently accessible refill options, a bottle or flask that holds 12 to 20 ounces (350 to 600 milliliters), like the Osprey Duro/Dyna Handheld, will likely be sufficient. As the mileage increases and the weather warms up, you’ll likely need a capacity of at least 20 ounces (500 to 600 milliliters) to maintain hydration.

In very hot temperatures, longer runs, or for those with higher sweat rates, additional bottles may be necessary to keep up with hydration needs. A hydration pack makes running with multiple bottles easy, or you can choose to use a single larger water bladder that holds a liter or more.

You can also carry more water with a waist pack and one or two handheld bottles. If you want to increase your water-carrying capacity without carrying a full pack, check out our best running belts guide.

What is a soft flask?

A soft flask is a soft-sided collapsible bottle made of TPU or silicone. It typically holds 12 to 20 ounces (350 to 600 milliliters) of fluids and has a bite valve that allows easy drinking while moving. The one-way bite valve keeps excess air from entering the flask as it empties, so liquids don’t slosh around, even if it isn’t completely full.

The lightweight flasks collapse flat once empty and are easy to stash in a pocket or pack. Our favorite soft flask is the Hydrapak UltraFlask Speed 500ml. Some soft flasks have a bite valve that will lock to prevent accidental spills.

The Katadyn BeFree Water Filtration System 0.6L makes it easy to filter water on the go and fits in most hydration pack pockets. Photo: iRunFar/Eszter Horanyi

How much water should I carry on a run?

Weather conditions, terrain and environment, and your natural sweat rate all affect the amount of liquid you need to carry. Note that for longer and hotter runs, you’ll also need electrolytes to replenish what you lose as you sweat.

According to Kristen Davis, who has a Master of Science (MS) and is a registered dietician (RD), as well as a board-certified specialist in sports dietetics (CSSD), “Carrying fluids on a run helps you get the most out of your workout. Even mild dehydration can negatively impact your training and performance.”

She says it’s important to calculate sweat loss during different conditions and activities so that you can carry enough fluids during a workout to make up for that loss. Based in Utah, Davis operates Run on Fuel, where she helps distance runners, triathletes, cyclists, and other athletes maximize their performance and meet their nutrition needs.

Davis says, “To determine your sweat loss, weigh yourself (naked) before and after the run or workout you want to assess. Using a towel to wipe off any additional sweat remaining on your body after the workout is important. If you will be consuming fluid and fuel during the run, make sure you weigh your bottles and fuel before and after so you can account for that. This will give you a pretty accurate assessment of how much you sweat during that type of workout and in those conditions. 

“Once you have that information, you can break it down to sweat rate per hour and carry roughly that amount of fluid with you on your future workouts (keeping in mind you will probably not drink all of it).”

A small and unobtrusive water-carrying system, such as the Osprey Duro/Dyna Handheld, makes it easy to grab some water whenever you go for a run. 

Jim Walmsley runs with two handheld bottles during the middle of the 2024 Western States 100. Photo: iRunFar/Eszter Horanyi

How much water should I drink on my run?

The rule of thumb for shorter runs or workouts is to drink to thirst. Drinking too much water, especially without sodium or electrolytes, can lead to hyponatremia.

Davis says, “For workouts longer than 60 to 90 minutes, I do not recommend drinking much plain water. For longer or harder workouts, it’s very important that your primary source of hydration is coming from a sodium-containing sports drink.

“To determine how much you should be aiming to drink, it’s helpful to have an idea of your sweat rate (mentioned above). A good goal is to drink 50% to 75% of your losses. For example, if you lose one liter of sweat per hour (about two pounds or 32 ounces), a good goal would be to drink 16 to 24 ounces of your sports drink each hour.”

Having a water bottle, like the Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series, waiting in your car after a run, can make it easy to drink water after a workout and start the rehydration process as soon as possible.

I get hot when I run and dislike wearing hydration packs. What are the best bottles for me?

Handheld bottles or soft flasks, like the Osprey Duro/Dyna Handheld and the Amphipod Hydraform Jett-Lite Thermal Handheld 20 oz., are the easiest way to carry hydration without a pack. Many companies make different designs, but they all incorporate a hand strap that helps secure the bottle to your hand so you don’t have to grip it tightly to carry it. There are multiple sizes and styles to choose from, but most of them max out at 20 ounces.

A waist pack or belt is one option for carrying more fluids without wearing a vest or pack. Several options can hold one or two bottles. Check out our best running belts guide for some of our favorites.

What bottles are compatible with my hydration pack?

Most hydration packs will come with either a bladder or a set of water bottles that fit the pack’s pockets. However, many bottles — especially soft flasks — can be used interchangeably across a wide variety of running vests. The key is whether the size and shape of the bottles are compatible with the vest’s pockets.

Most hydration vests generally have pockets that will fit flasks that are more elongated or shorter and wider. If the bottles don’t fit properly into a vest pocket, they can flop around or fall out, so it’s important to double-check the pack specifications or contact the manufacturer with specific questions about your pack and which soft flasks it will carry properly.

Our favorite soft flask, the Hydrapak UltraFlask Speed 500ml, fits a large number of hydration vest pockets, while the UltrAspire UltraFlask 550 Hybrid Bottle works for packs from the brand. That said, even these bottles can fit in vests from various other brands as long as the pockets can hold long and skinny soft flasks.

While most brands design packs for soft flasks, some can still hold a hard-sided bottle. Our best running vests guide offers more hydration pack options.

A hard-sided water bottle can withstand everyday use and keep water from spilling. Photo: iRunFar/Eszter Horanyi

What size bottle is best for hiking, travel, or everyday use?

Many of the same factors mentioned above for running bottle capacity play a role in choosing a bottle for everyday use. The durability and incredible insulative properties of the Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series made it a go-to for many of our testers, and we’ve been using bottles from this brand for many years.

Generally, a 20- to 32-ounce bottle is a good size that transitions well from your workspace to the trails. The larger capacity reduces the number of refill trips needed during your workday and holds enough to keep you hydrated on a hike, road trip, or cross-country flight.

The shape of the bottle is also something to consider. A tapered bottom or long slim bottle will fit in a car’s cupholder or backpack side pocket much better than one with a wider base.

Is a plastic or metal bottle better?

Plastic bottles, like the Tracksmith Insulated Water Bottle, are typically much lighter than their metal counterparts, which makes them a better choice for running or other activities where gear weight has a significant impact. They are also squeezable and compressible, making them less susceptible to dents and dings, easier to drink out of on the go, and easier to store when not in use. To avoid potential chemical leaching, choose BPA-free products.

On the other hand, metal bottles, such as the Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series, are very durable and can withstand being dropped and tossed around without breaking. However, if you are rough on your gear, you might end up with some scuffs and dents.

This makes them an excellent option for everyday use, hiking and backpacking, yoga, and travel, though they are too heavy and cumbersome for running. Additionally, insulated metal bottles will help hot and cold drinks maintain their temperature for a long time. We recommend food-grade stainless steel bottles over aluminum bottles if you choose a metal option, as they have a lower risk of leaching chemicals and will not retain odors or stains.

How are bottles insulated?

Insulated bottles, including the Tracksmith Insulated Water Bottle, have an inner and outer layer of material, either plastic or stainless steel, with air between the layers that act as a barrier to reduce heat transfer between the bottle contents and the outside environment. Some insulated metal bottles vacuum seal the area between the two layers to reduce energy transfer even more.

When it comes to keeping hot liquids hot and cold drinks cold, water bottles with this double-wall insulation, like the Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series, are the best. Some bottles and soft flasks use a thicker foam-like material to prevent heat transfer and keep liquids inside cooler longer. These flasks can only be used with cold liquids and are less effective than a double-wall system.

Finally, in addition to adding insulating properties to the bottle, some companies use a sleeve around the bottle to add even more insulation. The Amphipod Hydraform Jett-Lite Thermal Handheld 20 oz. has a removable insulating sleeve to help keep liquids cool, but it doesn’t work as well as double-wall insulation.

Hard-sided water bottles are great to have on hand during track workouts or runs where you end up in the same place multiple times. Photo: iRunFar/Eszter Horanyi

Can I use my bottle for both hot and cold liquids?

Most plastic bottles and soft flasks cannot withstand high temperatures, so filling them with hot liquids can damage them, including warping the bottle or causing leaks at the seams. You can use double-wall insulated plastic bottles, like the Tracksmith Insulated Water Bottle, in cold weather with warm fluids to keep them from freezing, but you shouldn’t use them for very hot liquids or boiling water.

Non-insulated metal bottles should not be used with hot liquids, as the metal will transmit heat and cause the outside of the bottle to become very hot. This could damage gear that comes in contact with the bottle in your pack and may burn your hands.

Most double-wall insulated stainless steel bottles, like the Hydro Flask 32 oz. Lightweight Wide Mouth Trail Series, can accommodate hot liquids and keep them warm for hours without transmitting that heat to the outer layer of the bottle. However, use caution when drinking warm beverages from these, as they do their job so well that the fluids might still be too hot when you take a sip!

Call for Comments

• What’s your favorite water bottle for running?
• Do you have a collection of water bottles for different uses?