10 Best Soft Flasks Tested
Hydration is key to having a good run. Drinking water before, during, and after your workout improves cardiovascular performance and health, keeps you cool, improves the performance of your muscles and joints, and cleanses your body of toxins, among other benefits.
Fortunately, hydration technology has advanced quite a bit from the days of cross body canteens. Runners now have the option to use water bladders in conjunction with a matching carrier. However, you don’t always want to wear a hydration pack or belt, or even carry a clunky water bottle. Luckily, soft flasks have been invented, allowing you to stay hydrated on your run while not having to carry around a water bottle for miles and miles. Not all soft flasks are created equal, though. To see the best soft flasks on the market today, read our list of the 10 Best Soft Flasks.
10 Best Soft Flasks
Each flask in this set hold 700ml/23 ounces of liquid. These are only suitable for cold beverages.
These soft flasks are made of BPA-free, food grade materials. The hard snap lid will keep your flask closed, but users note that it must be closed very tightly or else you will experience leakage. Users also felt these flasks were awkward to hold because of a large plastic trim along the outside of the bottle.
Users report that this water bottle lasted through a variety of activities, including traveling, hiking, and running. Some users did report some leaking after about a week of use. Users also reported leakage from the cap.
These are very inexpensive soft flasks, especially for being a set.
- Safe materials
- Potential for leaks
- Not comfortable to hold
3. Hydrapak SF 150
This soft flask holds approximately 5 ounces of liquid or gel. The small size of this flask has many users stating that they use it exclusively for gels because it doesn't hold enough water to keep them hydrated on a run.
This Hydrapak SoftFlask is made of TPU to give it superior flexibility and durability. The removable top makes this flask easy to clean, which is especially important after filling it with an energy gel. It collapses for easy storage, but does not have a strap or hook to securely shut it or attach it to your clothes.
The TPU construction and welded seams make this bottle extremely durable against wear and tear and leaks.
This is a very low priced soft flask, which makes sense due to its small size.
- Can be used with liquids or gels
- TPU construction
- Users say it is too small for water
- No security strap or hook
This flask holds 8 ounces of liquid. It is only suitable for cold liquids.
The Salomon Soft Flask is made of PVC-Free TPU. It can be folded small enough to fit in the palm of your hand, but has no closing strap or fastener to attach it to your outfit. Users report this bottle has an odd smell that never goes away. As a result, some users purchased a replacement flask after just a short time.
TPU is an extremely durable material, so this soft flask can stand up to bumps and drops. Some users report leakage after only a short period of use.
This is an average priced soft flask.
- TPU construction
- Very small when collapsed
- May leak
- Funny smell
- No strap or hook
This soft flask holds 22 ounces of liquid.
This bottle is made of medical grade, BPA-free silicon. The double-lid has a water tight seal, so it won’t leak when upside down or squeezed. It can hold cold or hot beverages ranging from -60 degrees to 200 degrees. A carry strap also secures the bottle in its rolled or folded form. This flask can stand on its own once filled, eliminating the need to constantly hold or store it. This makes it a great choice for work, school, or training.
Silicone is highly durable, so this soft flask can withstand being dropped on even the most rugged running trail. There were no user reported leakage issues with this flask.
This soft flask is priced below average.
- Real water bottle shape
- Carry/security strap
- Holds hot and cold beverages
- Does not necessarily hold the temperature of liquids
This flask holds 17 ounces. It holds cold liquids only.
This bottle is made of collapsible BPA-free material. Even with welded seams, it weighs only 28 grams. The bite valve helps keep air out, preventing the water from sloshing around inside the bottle while you run, eliminating the potential for distractions or gait disruptions.
Although this bottle is highly durable and leak proof, users report that it may be too much so. The leak-proof cap is reported to be very difficult to open and close, so users recommend using a different bottle while racing. However, users also note that it is a great choice for people that throw their water bottle into their bag or purse, because it definintely won't leak!
This is a slightly below average priced soft flask.
- Leak proof
- Very lightweight
- Top is hard to open and close, so not good for races.
This bottle holds 26 ounces. It can hold cold beverages with ice, or it can hold moderately warm drinks, up to 100 degrees.
FDA approved, BPA-free medical grade silicone was used to construct the ITYYT Collapsible Water Bottle. It can withstand temperatures from -40 to 100 degrees, holding both cold and hot beverages. It is also capable of accommodating ice cubes for those runners that enjoy a freezing cold drink during their workout. After rolling up, this soft flask can be held securely with a strap.
Silicone is highly durable, and can withstand being dropped on a run, thrown into your bag, or a cycle through the dishwasher. The lid seal and valve are leakproof, and the cap keeps out dust and debris. Some users report that the closure strap fell off after a few uses.
This is an inexpensive soft flask.
- Hot and cold beverages
- Wide mouth for ice
- Questionable durability of security strap
8. Katadyn BeFree Water Filtration System
The Katadyn BeFree Water Filtration System holds 20 ounces of water. Water is the only liquid that should be used it this flask.
This collapsible soft flask is equipped with a .1 micron water filter, which can remove potential harms from your drinking water, including Giardia and Cryptosporidium . It has an EZ-Clean Membrane which tidies up with just a slosh of water.
The flask portion of this bottle is highly durable, but users have some reservations about the filter. The advise being extra gentle with it, as the small components can be damaged really easily. Replacement filters are available for purchase from Katadyn.
This is a high priced soft flask. The high price is a result of the filtration system that is built into the bottle.
- Water filtration system
- Easy to clean
- High price
- Filter is fragile.
9. Ultimate Direction Bottle with Kicker Valve
This soft flask holds 14 ounces. It is suitable for cold liquids only.
This soft flask is made of TPU. It is clear so you can easily see how much liquid is left in the bottle, keeping you aware of when it is time to fill up. The nozzle is a high flow bite valve, so getting a swig of water on your run is quick and easy. This feature is especially convenient while racing. Users noted that the fill head is very small, making filling this flask a difficult, messy task.
TPU is a highly durable material and is dishwasher safe.
This is an average priced soft flask.
- TPU construction
- Diswasher safe
- Small fill head
This soft flask holds 16 ounces of liquid. Only cold liquids should be used in this bottle.
This water bottle is BPA free. The bite valve speeds up hydration, which is a nice feature to have during a race. The two piece cap comes apart for easy cleaning and filling, ensuring that your water is always of high quality. Its collapsible and conforming shape makes it easy to store or pack on the go. Many users commented that the bottle made their water taste bad, even after washing it multiple times.
Users noted that even though this flask feels very thin, it is highly durable. It can withstand being thrown into your bag or a drop on a rugged trail.
This soft flask is priced slightly below average.
- Low price
- May make water taste badly
If you are in need of packable hydration on the go, a soft flask may be a option for you. They are light, stowable, and easy to fill and clean. Use this review of the Best Soft Flasks to help choose the bottle that will keep you running for miles and miles.