Mountain Warehouse Waterproof Bivvy Bag tested: the budget bivvy for beginners

Need a budget bivvy bag for summer nights? The Mountain Warehouse Waterproof Bivvy Bag might be exactly what you're after.

from Mountain Warehouse
RRP  £29.99
James Forrest in Mountain Warehouse Waterproof Bivvy Bag with LFTO star rating

by Chris Williams |
Published on

Bivvy bags are the minimalist's tent, and this Mountain Equipment bivvy bag is as simple as they come – but sometimes simplicity is all you need. For anyone giving bivvying a go for the first time, for budget-conscious bivvy users, or for those planning to bivvy only in mild, tranquil conditions, this basic bivvy bag will do the job at an affordable price.

It’s lightweight (363g), packable and waterproof, with an adjustable hood and a storage sack. The RRP is £40, but you can usually pick one up for even less. That’s a bone fide bargain.


  • Very affordable
  • Ultralight and packable
  • No frills design is quite refreshing
  • Adjustable hood


  • Much lower waterproof rating that most rivals
  • Not partiuclarly durable


James Forrest sitting up in Mountain Warehouse Waterproof Bivvy Bag

Made from a 63-denier 100% ripstop polyester, this bivvy bag feels reasonably tough and strong, and it is billed as waterproof and breathable by Mountain Warehouse. The design is the time-tested style used by almost all basic bivvy bags – a waterproof sack with a single top opening and an adjustable hood. The hood adjustment can be cinched in quite tightly, but it can never be fully sealed up, so there is always an inherent exposure to wind and rain.

The all-round build quality is fine, but far from premium. The drawstring design looks a little clunky and cheap, and we’d be a little doubtful about the long-term waterproofing and breathability capabilities of this bivvy. More time is needed for testing to comment on its long-term durability too.

Mountain Warehouse Waterproof Bivvy Bag toggle

Having said that, affordability is exceptional and the design and build quality are appropriate for the price-tag. If used in drier conditions and not thrashed about on super-rugged terrain, we’d suggest this basic bivvy should fit the bill – and, joyously, leave some extra money in your pocket for a post-adventure flat white and millionaire shortbread.

Size, weight, and packability

Mountain Warehouse Waterproof Bivvy Bag in stuffsack

If you don’t want your wild camping backpack to be heavily weighed down, this minimalist bivvy is a great gram-saving choice. It’s ultralight at just 363g – one of the lightest bivvies out there. The bivvy bag itself weighs 348g and the little carry bag weighs 15g. Of course, this lightness comes from the simplistic, no-frills design, so you do sacrifice a degree or two of protection, comfort and durability for the lower weight – but for many campers this will prove a viable trade-off.

The Mountain Warehouse Waterproof Bivvy Bag packs down nice and compactly to 25 x 10cm, not far off the size of a 1L Nalgene bottle. It packs away into a little storage bag, which has drawstring closure.

In terms of its official dimensions, there is a bit of confusion. A little graphic on the storage bag states the bivvy bag is 246cm long, 83cm wide at the head end and 50cm wide at the footbox, but the Mountain Warehouse website says it’s 225cm in length and 75cm wide. Based on our measurements with a tape measure, we’d suggest the latter is more accurate. It probably depends on how tightly you stretch out the fabric.

James Forrest lying down in Mountain Warehouse Waterproof Bivvy Bag

Certainly the Mountain Warehouse Waterproof Bivvy Bag is quite a large bivvy, with a good internal volume easily capable of accommodating a sleeping bag, sleeping mat and your body. There’s even space below your feet for a small backpack, potentially. The bivvy has a similar footprint to the large-sized Rab Trailhead Bivi and Alpkit Hunka XL, although the Mountain Warehouse bivvy is a touch narrower. It has more of a long and thin profile, with a gentle taper towards the feet.

For some campers the Mountain Warehouse Waterproof Bivvy Bag may be too big, with too much excess fabric at the feet, and an all-round cut that’s not snug enough. Taller and broader campers may welcome the extra wiggle room.

Waterproofing and breathability

James Forrest camping with a Mountain Warehouse Waterproof Bivvy Bag

Mountain Warehouse says this bivvy bag has a “waterproof membrane which prevents water from leaking through the fabric”, as well as “taped seams to ensure this product is completely watertight” – but the product listing on the Mountain Warehouse website does not list a hydrostatic head rating.

After a few enquiries, the company’s PR team told us that the hydrostatic head rating of the bivvy bag is 3,000mm, which is technically waterproof, but far from a top-end waterproofing rating. Many other bivvy bags we’ve tested have a 10,000mm or 20,000mm rating, so 3,000mm is rather disappointing.

The Mountain Warehouse Waterproof Bivvy Bag is also billed as breathable, but the company’s PR could not provide us with an MVTR breathability grade.

Taking all of this into account, we’d suggest this is a bivvy bag for drier camps in spring and summer, and certainly not one for atrocious weather. This is because – regardless of the fabric’s technical performance – the opening cannot be 100% sealed up, so your head and face will always be exposed to the elements. As with all bivvy bags, condensation will also be difficult to avoid in the UK’s weather.


Mountain Warehouse Waterproof Bivvy Bag hood

There a very few frills on this bivvy bag, as one would expect. The only thing to note is that the Mountain Warehouse Waterproof Bivvy Bag has an adjustable hood. The hood is slightly angular in shape and below it is an oval, ellipse-shaped opening. The opening is adjustable via a drawstring on one side. This can be cinched in quite tightly, but never fully sealed up, and the drawstring toggle is protected by a little fabric reinforcement.


James Forrest in Mountain Warehouse Waterproof Bivvy Bag with LFTO star rating

The Mountain Warehouse Waterproof Bivvy Bag is a super-simplistic bivvy bag for drier spring and summer camps, at a bargain price-point – but the build quality feels a little cheap and it's lacking in weatherproofing compared to other bivvies.

How we tested

James Forrest testing gear for Live for the Outdoors

We tested the Mountain Warehouse Waterproof Bivvy Bag in the Lake District in spring alongside a selection of other bivvy bags as part of a group test.

James Forrest (above) conducted this test and review. James is one of the UK's most authoritative and high profile voices on wild camping and backpacking, being a prolific peak bagger and experienced freeland outdoor writer.

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