Review: Hydrapak SoftFlask Collapsible Bottle

Inexpensive, Collapsible and Useful

Hydrapak Softflasks (multiple sizes)

I'm a big fan of collapsible water bottles for travelers. Done right, they offer the best of both worlds, letting you stay hydrated and avoid plastic waste from disposable bottles, while not taking up much space in your daypack when not in use.

I've reviewed a few different models in the past (check out the Stash, Shades and MicroFilter varieties), and Hydrapak sent out its latest offering, the Softflask, to see if it'd make the grade on a hiking-based trip to New Zealand. Here's how it did.

Features and Specifications

Like its Stash stablemate, the top and bottom of the Hydrapak Softflask are made from a rigid plastic, while the sides use a soft, lightweight rubber that squashes down when the bottle isn't in use. That's where the similarities end, however.

With a rounded base, the Softflask isn't designed to stand up by itself and doesn't use the twist-to-compress approach of the Stash. It's intended to be held in the hand, placed in a bag or attached to a backpack via the included nylon strap, and simply squashed up to minimize space.

Dispensing with the Stash's basic screw-cap opening, the Softflask has a fancier alternative. The lid mechanism unscrews completely to allow quick filling and emptying but uses a high-flow bite valve to dispense water while drinking. There's a locking mechanism to prevent accidental leakage, and a cap to ensure dust and dirt don't get into the valve.

The bottle comes in three sizes – 350ml, 500ml and 750ml – and three colors. It weighs 1.8-2.3oz depending on size and is dishwasher-safe. Frozen, cold and warm liquids are fine, but it can't handle very hot or boiling water.​

Real World Testing

I used the smallest member of the range, the Softflask 350 that holds 12 fl. oz.

Screwing and unscrewing the lid was straightforward, and given the bottle's small size, it only took a few seconds to fill from a kitchen tap. It took a little longer to get the hang of the locking mechanism, however – initially I found myself unscrewing the lid instead of unlocking it. The key was to only turn the nozzle, not the entire lid, and once I'd figured that out, it worked flawlessly.

The bite valve lets through a good amount of water when accompanied by a gentle squeeze of the bottle. I didn't need to break stride to stay hydrated even when walking at a brisk pace, and there was minimal leakage from the valve even when it wasn't locked. When locked, there was none at all.

As well as taking up less room in my bag than a traditional rigid bottle, the collapsing sidewalls had an extra benefit – reduced sloshing, even when the Softflask was nearly empty.

Given its small size, the Softflask 350 was ideal for handheld use, and that's how I ended up using it on day hikes and extended walks around the city. Since this model didn't hold enough water to last an entire day in warm conditions, I also carried a larger bottle in my day pack and refilled the Softflask as necessary.

As the bottle emptied and started to collapse on itself, I found I could still hold and use it easily in one hand just by applying a little extra pressure. Once drained of water, I removed the remaining air via the bite valve and squashed the bottle into a compact ball to store in my bag.


I ended up liking the Softflask more than expected. While it doesn't have the twist-and-click approach of the Stash, the addition of a bite valve made it more useful overall. Being able to drink while walking made it perfect for hikes, and the small size fit easily in one hand.

The 350ml size was a little limiting – when traveling to warm climates or if you're regularly out exploring for several hours, I'd recommend one of the larger 500ml or 750ml models unless you don't mind also carrying a larger bottle to refill it from.

For shorter walks or colder climates when you don't need as much hydration, however, the Softflask 350 is a very handy, useful travel accessory.

You'll typically pay under $20 for the Softflask – check prices on Amazon.

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