The Borah Gear Cuben Bivy: Well used review

First Impressions & Build Quality

The Borah Cuben Bivy is all about minimalism. Borah is a Montana-based cottage company making ultralight shelter components like tarps, bivys, and groundsheets.

Built from Dyneema Composite Fabric (DCF), it immediately stands out for its incredibly low weight and clean, no-frills design. I bought the bivy second-hand, and the specifications aren't the lightest in the lineup. I have all the extras here, including the side access zip (great when paired with a side-entry tarp) and a long and wide footprint. If I were to buy again, I’d probably skip the long variant, but I’d definitely keep the width. The choice of materials is excellent, and all the sewing is neat. After a few years of hard use, I see no signs of wear or tear, thanks to careful handling.

Performance in the Field

Scottish Rain & Boggy Ground

Scotland is where gear either proves itself or fails quickly. Persistent rain, saturated ground, and unpredictable wind make it an ideal testing ground.

The standout feature here is the bathtub floor and splash protection. Whether pitched on damp grass, uneven ground, or dealing with wind-driven rain, the bivy consistently kept ground moisture and splashback at bay. I never had issues with water ingress, even in less-than-ideal campsite selections—at least not due to the bivy bag.

I would note that I pair the underside of this bivy bag with the ULfoam mat to prevent punctures to the waterproof layer of the DCF flooring. I’d advise adding something here as a groundsheet. The specs of DCF are very thin (which is what we want), but from experience, it can puncture fairly easily.

Thunderstorms in the Dolomites

I’ve had the pleasure of being completely soaked in this bivy during a few thunderstorms. Water came into the head of the bivy with wind-driven rain through the open end of my tarp door. This was due to a poor choice of tarp and pitching for the weather conditions, not the bivy itself.

One gripe here is that the footbox of the bivy, when fully saturated, gets very stuck to the quilt I was using inside. To combat this, I’ve sewn an extra chord tie-out to the bottom of the bivy and attached it to the inside of my tarp. This means that if it gets soaked again, I’ll be slightly more comfortable.

Condensation & Moisture Management

I was sceptical after reading reviews of poor condensation management. However, paired with my Enlightened Equipment quilt, I experienced virtually no condensation or moisture issues, even in damp Scottish conditions. That’s something I’ve struggled with in other bivy setups.

Weight & Packability

This is one of the bivy’s strongest selling points. It sits firmly in the ultralight category, and when you're counting grams on longer trips, it makes a noticeable difference. It packs down small, disappears into your kit, and doesn’t feel like a burden even on extended hikes with significant elevation. The DCF stuff sack supplied is a nice touch.

The long and wide variant I’m using now comes in at just 150 grams. For the price, this is extremely competitive and among the lightest splash-protective bivy bags on the market.

The Downsides

No piece of gear is perfect, and the biggest limitation here is space. Even in the long/wide version, the interior feels tight. Once you're inside with a sleeping pad and quilt, there’s very little extra room to move. Compared to other bivys in a similar weight class—particularly offerings like the Hyperlite Mountain Gear Splash Bivy—the Borah feels noticeably more restrictive. The big jump in price there may make it worth this little niggle.

Who It’s For

The Borah Cuben Bivy is best suited for:

Final Thoughts

After extensive use in genuinely demanding environments, the Borah Gear Cuben Bivy has proven itself to be a highly capable ultralight shelter component. Its strengths are clear:

We will be using it again this year on the Hebridean Way, among other trips, and look forward to many more nights on the trail!

Check out the Cuben Bivy by Borah here: https://borahgear.com/cubenbivy.html