Rei Minimalist Bivy Sack Review

REI Minimalist Bivy Sack

Buy the REI Minimalist Bivy Sack


I purchased the REI Minimalist Bivy Sack in Boulder Colorado mid tour on my last cross country ride. It was one of those sales at REI and my sleeping bag needed replacing badly. I picked up a cheap summer bag and noticed the bivy marked down from $89 to $59. I don’t know why it was marked down. I gave it a quick once over and it seemed to be in perfect condition. MINE!


I was carrying a 10-year-old Sierra Designs Clip CD2 2 person tent and figured that I could drop some serious heft and weight by grabbing the REI Minimalist Bivy Sack. I made the purchase and sent the tent home in the mail.

I used the REI Minimalist Bivy Sack for the next 25 days of bicycle touring as my main shelter paired with a poncho/tarp. I have also used the REI Minimalist Bivy Sack in winter conditions in Upstate NY on weekend getaways into the woods. Here are my findings on the REI Minimalist Bivy Sack. It’s strengths and weaknesses and how to use it best.

The REI Minimalist Bivy Sack is Waterproof

This REI Minimalist Bivy Sack has proven itself to be as waterproof as waterproof gets. Constructed of ‘Breathable REI Elements laminate’ bonded to a ripstop nylon shell featuring a durable nylon taffeta floor and factory-sealed seams makes this a good durable first bivy.

The REI Minimalist Bivy Sack does require an additional cover. I see a good number of comments on the REI page as being negative about the top of the bivy being open. I don’t know how anyone could have bought this and not realized that the opening mesh area that sits atop your face needs to be under cover.

There are other bivys with a complete weather seal but this is not the case here. The face area of the REI Minimalist Bivy Sack stays open to the weather and allows you to breathe. If you allow rain to fall on top of your head area it will puddle in the bivy. I have used a poncho, a garbage bag, a tarp, an umbrella, and even the base of a spruce tree to cover the head portion of the bivy. If your head is covered you will remain dry from rainfall. I find the rest of the bivy to be waterproof and have never woken up with a wet sleeping bag due to outside precipitation. I have slept in steady rain with up 60% of the bivy exposed and remained dry. I have slept in a snowfall of 14 inches and was warm and toasty inside my REI Minimalist Bivy Sack.

REI Minimalist Bivy Sack
Buy the REI Minimalist Bivy Sack

the REI Minimalist Bivy Sack and Breathability

Cmon….really…Breathability? This is a dirty word. If it is hailed as ‘waterproof’ it will only ‘breathe’ under optimum conditions. Optimum conditions are available NEVER.

Companies bandy around the breathable card without ever really explaining what it means and how to actually attain it. I have seen condensation when using the REI Minimalist Bivy Sack but not to the degree that would cause me to replace it. My simple rule is to have my head outside the bivy to make sure my breathing is not filling the bivy with water. The mesh bug panel can be rolled down and toggled open to make this easy.

Note: I would love to see a bivy manufacturer come up with a feature where you could open or unzip the toe box allowing for ventilation to pass completely through the bivy top to bottom. I realize this would add more weight, and possibly make for points where water could get in. Most times I am in the bivy it is used more as a splashguard while under a tarp and to be able to eliminate condensation worries on nights that there was no rain would be a big upgrade.



The REI Minimalist Bivy Sack and Zipper Madness

Too many zippers? This thing has way too many zipper heads. When I get inside my bivy it’s basically lights out. I have never felt the need to have access to ‘this or that’ once I am in the bivy. There is no amount of openings that will make a bivy more convenient for someone who is prone to fumble around after deciding to get inside their bivy. It’s a bivy after all. Get in and go to sleep. At least they they are nice quality zippers. They could be clipped off and replaced with ties if you were a real gram weenie. At 15 ounces there are lighter bivy choices on the market. The zippers add some weight. I just find them a tad bit unnecessary.

Sleeping Pad Shape for the REI Minimalist Bivy Sack

Got a square sleeping pad? I have an old school square thermarest pad and while it does fit inside the bivy you can see that the more modern rounded edge sleeping pads or any mummy cut pads fit much better. This isn’t really a complaint because the square pads do work. They restrict some of the space inside the bivy and space in a bivy is at a premium. Take this into account if you are shopping for a pad to mate with your bivy sack. Get one with rounded corners. Read my Thermarest pad review Thermarest Old School vs. New School.

Are You Able To Sleep In A Bivy?

Sleeping in a bivy is pretty challenging. I am able to sleep comfortably in a bivy even in a driving rainstorm. A tent offers a place to relax and take a break from the exposure. A bivy does not. Try changing clothes in a bivy. I wrote a whole post on this: Do you have a Bivy Sack Personality?

I Recommend the REI Minimalist Bivy Sack

I completely recommend this product to anyone who wants an entry level bivy that does not mind a little extra weight. I love the freedom that the bivy gives me when I am confident that it isn’t going to rain. Someone once asked me how many sunsets I would get to see before I die. I’ll probably spend less nights sleeping out in the open under the stars than I will see sunsets. Any gear that can help increase that number goes along on my tour.



Buy the REI Minimalist Bivy Sack

REI Minimalist Bivy Sack – Manufacturer Specs

Seasons: 4-season
Sleeping capacity: 1-person
Weight: 15 ounces / 0.43 kilograms
Packed size: 6 x 10 inches
Bivy length: 82 inches
Shoulder width: 32 inches