Eco Vessel Boulder

Keeping it hot or cold with the Eco Vessel Boulder

Eco Vessel Boulder

The Eco Vessel Boulder claims to keep liquids cold for 36 hours or hot for 8. We've been testing it out for the last few months.

Review Score

Our Score: 8.3/10

We've given the Eco Vessel Boulder the Thumbs Up award.

GOWTK Thumbs Up Award
Value for MoneyQuality

The good

  • We found the Eco Vessel Boulder flask kept to its promises of keeping liquids warm and cold. And it didn't leak.

The not so good

  • You need to shop around to find one at a good price. The cheapest we found was £9-10 but we did also find someone selling one for £68!

This was a hands-on product review. The product was supplied to us to test and conduct the review.

Price Guide

The best price we've found so far is £22.50.

Eco Vessel Boulder Videos

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Eco Vessel Boulder Photos

Eco Vessel Boulder

Eco Vessel Boulder

Our Review

A warm drink when the weather is cold, or a cold drink when it's hot, is always nice.

There are many options on the market these days; all handy sizes to fit into your backpack when out with the kids.

So, what makes the Eco Vessel different?

Eco Vessel started as a company aiming to reduce the use of non-environmentally friendly single-use plastic bottles by creating a range of reusable water bottles (and it also donates some of its profits to Water for the People charity).

They also aim to make their products with material that can be recycled, and where possible, made from recycled material.

The products are independently verified not to contain BPA, Phthalates, lead, or other potentially harmful materials.

The Eco Vessel Boulder

Putting aside the environmental credentials, the Eco Vessel Boulder is a great drinks container for both hot and cold drinks.

Eco Vessel Boulder features

The lid of the Boulder has a handy handle, which also contains a smaller opening for drinking straight from it. Alternatively, you could open the larger size and pour it into a cup.

Interestingly, the Boulder comes with a strainer that you could use for tea, infusing fruit, or even packing the Boulder full of ice and leaving the strainer in so that the ice doesn't fall out when you pour it. It keeps the ice from blocking the smaller opening if you drink directly from it.

Making Tea
On the picnic

Flask Insulation and Performance

How TriMax Works

The Boulder uses a triple layer of insulation, with some bold claims, such as keeping cold for 36 hours or hot for 8 hours.

Putting the Boulder to the Test

So we have a few things we look for in flasks like this:

  • Will it easily fit into our backpack?
  • Are there no leaks if tipped or shaken about?
  • Will it keep things hot or cold?

We've been using the boulder for a few months and have been very impressed with its performance.

It's a good size for one or two people sharing a drink. You might want a larger version if you want a single flask for the entire family.

It's also a great size that can easily slip into the side pockets of our backpacks.

As for leaks, there's been none, which is good :-)

ECO Vessel Insulation

We've not timed how long things have exactly stayed hot or cold, so we cannot verify the 36-hour or 8-hour claims, but in real-world use, it has stayed warm or cold when we've taken out for the day.

in real-world use, it has stayed warm or cold when we've taken out for the day


AttributeEco Vessel Boulder
Best Price£22.50
Product InfoBrand Web Page