You don’t have to be a pro runner to know that hydration is key to running your best and feeling your best. On longer runs and in hotter weather, you’ll want to carry water or other liquids and stay hydrated. The amount you need varies by individual, heat and humidity, and how well-hydrated you are before your run, but most runners should consider carrying water on runs longer than about 45 minutes to an hour. Options range from handheld soft flasks that fold up and stash easily in a pocket when empty to vest-packs that hold enough fluid for a full day. Find the right system for you with this guide to hydration systems made for runners, organized by the smallest capacity to the largest.

HANDHELDS

The smallest and lightest-weight hydration systems are carried by hand. They’re simple, fast to access, and a great choice for runners who don’t want to be encumbered by wearing a hydration system.  

Hand strap: These bottles use a lightweight, sweat-wicking strap that slips over your hand, so you don’t have to worry about gripping the bottle tightly or dropping it. Many come with small pockets for carrying things like a key or a gel.

Hard plastic bottle: Look for options that are shaped ergonomically for more comfortable carrying.   

Soft flasks: These are made from a flexible, collapsible material like thermoplastic polyurethane. When a soft flask is empty, you can fold it up and stash it away.  

Volume: Handhelds range in volume from about eight to 22 ounces. The right size for you will depend on the length of your runs and the conditions. 

Mouth opening: This is the cap you unscrew to fill the bottle or flask. Wider openings make bottles easier to fill and clean. 

Mouthpiece (or bite valve): This is what you drink from. Flow rates vary, so look for one you like. Some mouthpieces seal shut when not in use, which minimizes leaking.

Switch it up: Over time, using one hand exclusively can lead to muscle imbalance, causing discomfort or pain. Switch hands routinely.  

WAIST-MOUNTED BOTTLES OR FLASKS 

Hydration systems that fit around the waist are great for runners who want a minimalist option that leaves their hands free. Like handhelds, waist-mounted packs use both bottles and soft flasks. 

Stability: Waist packs are designed to stay secure and stable, but some bounce much more (or less) than others. Check fit and bounce before buying. 

Ease of use: A key consideration with this style is how hard or easy it is to access bottles and put them back while running. Test this while shopping: Try the waist pack on, take a bottle from its holster, and return it to the holster.

Features: Most waist packs have pocketing built into them for carrying small items. Some can accommodate a lightweight jacket.

Waist-mounted with Bottles: Most waist packs with hard bottles carry two or more small bottles instead of one large bottle, which helps distribute the weight of the liquid, reducing bounce. These bottles generally carry around 10 ounces of liquid each. Bonus: A system with multiple small bottles lets you carry water and other hydration fluids in separate bottles.

Waist-mounted with Soft flasks: This design tends to hold one larger (20 ounces or so) soft flask horizontally at the small of the back. The soft nature of these bottles allows them to conform to the shape of the body and stay balanced as they empty. 

HYDRATION PACKS

For the longest outings, running-specific hydration packs carry the most water and have the most versatility. These packs are smaller and lighter than traditional backpacks, and are designed to minimize bouncing. Packs accommodate hydration bladders or soft flasks, and often both (hard-sided bottles are less common). Sometimes these are included, sometimes not. Most use a vest-like design that puts snack pockets and flasks in front, where you can access them easily.  

Pack with Bladder

Running packs typically have storage compartments on the back that are smaller and narrower than traditional hiking backpacks. Look for extra straps down the sides designed to minimize pack movement. Bladders generally range in size from 1.5 liters to 2.5 liters. 

Vest-Pack with Soft Flasks

Packs that fit like a vest, with large pockets on the front and continuous mesh versus skinny straps on the sides of the body, often hold soft flasks in the front pockets. Some flasks come with straws meant to allow easier drinking on-the-go (without taking the flask out of the pocket).

Vest-Pack with Bladder

These packs are often the most versatile, with a bladder in the back and soft flasks on the front.  They allow the most customization of the amount of water you carry. 

All articles are for general informational purposes.  Each individual’s needs, preferences, goals and abilities may vary.  Be sure to obtain all appropriate training, expert supervision and/or medical advice before engaging in strenuous or potentially hazardous activity.