Wild campingBig AgnesBivy
Super small yet remarkably robust — the most comfortable bivy we've tested, at a price that reflects its specialist credentials.
✓ Specialist ChoiceBig Agnes Three Wire Hooped Bivy
RRP~£340–400Weight694gShelter type3-4 season bivy
The good✓ Genuinely ultralight
✓ Very easy to pitch
✓ Robust 3-layer waterproof membrane
✓ Less claustrophobic than most bivies
✓ Full-length door zipper
The not-so-good✗ Eye-watering price vs simpler bivies
✗ Tight sleeping space (inherent to bivy design)
✗ Foot guys need to be elevated to avoid sag
At a glance
| Brand | Big Agnes |
| Model | Three Wire Hooped Bivy |
| RRP | ~£340 at Ultralight Outdoor Gear |
| Weight | 694g |
| Length | 211cm |
| Width | 61cm |
| Headroom | 51cm |
| Best for | Ultralight fastpacking, bikepacking, single overnighters |
| Not for | Multi-day backpacking in bad weather, comfort-focused camping |
Bivies are the smallest shelters out there — designed for adventures when weight and pack size matter more than anything else. They're here to keep you dry and out of the wind should conditions deteriorate in the night, and very little else. Most are notoriously uncomfortable. The Big Agnes Three Wire Hooped Bivy is a rare exception: a breathable, robust and relatively comfortable coffin-like shelter that's not only easy to carry but actually reasonable to sleep in, all things considered.
At 694g and packing down to roughly the size of a 500ml Coca-Cola bottle (even smaller with the pole packed separately), it's one of the smallest and lightest shelters we've tested. Available at Ultralight Outdoor Gear for around £340, it's at the top end of the price spectrum for bivies — the Alpkit Elan costs £99.99, the Outdoor Research Helium £199.99. For context, the Rab Ridge Raider (heavier, more robust) comes in at £420. At this price, the Big Agnes needs to deliver.

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We've been using the Three Wire Hooped Bivy for over a year across multiple adventures: several multi-day runs across Exmoor and Dartmoor, a bikepacking trip in northern England, and a fastpacking overnighter through the Thames Valley in autumn. We've used it in wind and rain as well as on calm comfortable nights, covering close to 200 miles with it in the bottom of our pack.

The pack size and weight are the whole point — and they're both exceptional. At 694g, it's the same as a standard basketball. Pack the pole separately and it squashes to roughly Nalgene-bottle size; with a dry bag you can get it even smaller. For fastpacking or bikepacking, this makes it a genuinely compelling option over a dedicated tent.
One pole, three peg-out points — it's almost as easy as rolling out a sleeping bag. The only design quirk: the guy lines at the foot end need to run over something higher than the bivy (hiking poles or a nearby tree) to keep the material off your feet. If guyed directly into the ground, the fabric rests over your feet all night — annoying and can create condensation on cold nights.

This is where all bivies show their fundamental flaw: there is none. You can't cook from inside it, you can't store kit (maybe a tiny amount at the foot end), and there's nowhere comfortable to wait out a rainstorm. Once you're in, you're in. That's not a criticism of Big Agnes — it's the nature of the category.
What the Three Wire does better than most bivies is everything else: the 3-layer waterproof nylon membrane feels more like a waterproof jacket than a tent fly, condensation is well-managed even in single-digit temperatures, and the full-length door zipper lets you zip in like draping a blanket rather than squeezing into a sarcophagus. Our 6'7" contributor Adrian was one of the only humans able to fit in it comfortably — the 211cm length is genuinely accommodating.

Our verdictThe most comfortable bivy we've tested — but know what you're buying.The Big Agnes Three Wire Hooped Bivy is tiny, easy to pitch, and remarkably comfortable for a shelter of this style. It's become our go-to bivy for fastpacking and bikepacking trips where weight and pack size outweigh everything else.At around £340–400 through retailers like Ultralight Outdoor Gear, you need to understand that you're buying a means to an end. A bivy is designed to get you through the night, not to be comfortable. This is the best we've tested in that category — but only buy it if that's genuinely what you need.
How does the Big Agnes Three Wire Bivy perform in summer?Well. A large vent at the head end allows for reasonable airflow, keeping condensation to a minimum even on muggier nights.
How easy is the Big Agnes Three Wire Bivy to set up?Dead simple — roll it out, add the pole. Prop up the foot end over hiking poles. The whole thing is ready in seconds.
How does the Big Agnes Three Wire Bivy handle wind?Well. Sitting so low to the ground, there's very little for wind to push against.
Is the Big Agnes Three Wire Bivy worth the money?At nearly £400, it's by no means cheap. But it's one of the most robust, comfortable and reliable bivies we've tested. If weight and pack size matter more than anything else, the price is worth it for the right person.