Runner's Guide to Soft Flasks

Marathon season is here, with Hyderabad in August, Mumbai in January, and the dozens of city runs in between, the Sunday long run quietly takes over the lives of runners in India. These runs are the backbone of every training block, and also where we learn the hardest lessons: pacing, nutrition, and most often, hydration.

Running those long 30km runs with a bottle in hand or stashed in a belt, is not the most convenient. By kilometre 10 we will start wondering why it’s bouncing or digging into our ribs. That said, carrying water during training is necessary for these long runs. We don’t get aid stations on our training routes, and running without water is asking for trouble.

Here is where soft flasks fit in. They’re small, flexible bottles made of TPU that collapse as you drink, so they take up less space and don’t slosh around. They fit easily into the front pockets of hydration belts, in the pockets of your running shorts or even can be held in your hand without breaking sweat.

The best thing is they collapse as you go, so by the time you’re halfway through your run, there’s no bounce or bulk. You can carry around 250-500 ml or even 500ml. They’re light, and once empty, they can just be tucked away in your vest. Another advantage is you don’t have to work hard to drink from a soft flask. You just have to bite and squeeze. You barely need to tilt the flask; just squeeze and sip.

What’s available in India

A few years ago, these were hard to find here. Now, there are some reliable options:

• TEGO/Pacer 200 ml – Indian brand; Compact option, and great value for money.
• Kiprun Soft Flasks (Decathlon) – Affordable and durable.
• Tripole Soft Flask (500 ml) – Indian brand; sturdy with a soft bite valve. Comes in a version with a hand strap for those who prefer carrying it.
• HydraPak Soft Flasks – Light, fast-flow valves. Pricier but worth it for regular marathoners.
• Aonijie Flasks (500–600 ml) – Well built. Does the job for training runs without costing a lot.
• Puma Running Soft Flask – Nicely built, a bit too tall, limited choice.

Prices range from ₹600 – ₹2,500 depending on brand and size.

A few small learnings

After using soft flasks through multiple training cycles, here are a few things we’ve learnt to get the best out of them:

• You can carry two smaller flasks instead of one large bottle — one for water, one for electrolytes.
• Label them or use two different colors - one for water, one for electrolytes; it saves mid-run confusion.
• Clean them after every use with warm water and air-dry. TPU doesn’t like being left wet for long.
• Test them before the long run day. They are a bit fragile and can leak.
• Don’t overfill. They’re designed to expand slightly, so please don’t overfill them.
• Material matters: The TPU ones (and BPA free) will collapse and sit flat when partially empty. Cheap Chinese plastics = bounce and weird taste.

Of course, a soft flask won’t make you run faster by itself, but it will remove one small gear headache so you can just run. When you’ve got 8, 10, 12 training weeks ahead of you, a soft flask is a great investment.

Compiled by Team GeeksOnFeet for the love of running