Best Ultralight Bivy Sacks for a Daring Camper

If you’re in a rush and want to find out what the best bivy sack is, we recommend the
GEERTOP Ultralight Bivy Tent.


Ah, the bivy sack. A backpacker’s best friend, and an item that you might never have even heard about unless you’re an extreme trekker or happened to catch wind of it in passing. Once thought of as the shelter for crazies, bivy sacks have steadily been gaining in popularity, especially in the ultralightweight backpacking community. We’ll cover some of our top picks below to help you find your next minimalistic shelter.

Bivy Sacks At A Glance

If you’re in a hurry, check out this quick list of our favorite bivy sacks – otherwise, keep on scrolling to get to the full reviews!

What is a Bivy Sack?

Bivy is short for “Bivouac,” a word that’s used to describe any improvised shelter for temporary use. These handy sacks allow you to roam freely through the wild without carrying the extra weight that comes with a tent. This isn’t an issue for people who don’t mind rolling their sleeping bag out on the ground and calling it good for the night, but for those of us who like a little more protection, bivy sacks are a lifesaver.

You can think of this item as a sleeping bag for your sleeping bag. It’s a sack that slides over your sleeping bag to provide a weatherproof layer between you and the open wilderness. Some come with a hooped rod that lifts the fabric around your face, so you don’t feel like you’re going to suffocate during the night. They definitely don’t make the most comfortable sleeping arrangements in the world, but they do the trick if you’re trying to shave a few pounds off your pack and still want something of a shelter.

Bivy Sack History

bivy sack in backpack of two rock climbers climbing up a big wall in yosemite national park

Bivy sacks were originally created for rock climbers spending the night on the wall. Since it isn’t possible to pitch a tent several hundred feet up the side of a cliff, bivy sacks were necessary for climbers who wanted shelter against the elements. Some brave campers would occasionally use them on long backpacking trips as well, but this was very much seen as an extreme (and slightly crazy) course of action for a long time.

It wasn’t until these sacks were adopted for use in the military that they finally started to gain popularity. Now they’re widely used by anyone wanting stay lightweight and mobile as they move from one location to the next.

Picking the Best Bivy Sack: Pros and Cons

Bivy sacks are incredibly useful, but they certainly aren’t for everyone. If you’re wondering if this is something that’s right for you (or a friend, if it’s a gift), take into consideration this list of pros and cons.

The Pros…

To start, the primary reason why outdoor enthusiasts use bivy sacks is because of how lightweight they are. When put side by side next to a tent, there’s really no comparison in this regard. Many of them don’t have a frame adding weight, unlike the poles that you’ll find in every tent, and the fabric is as minimalistic as you can get while still being protected.

The best bivy sacks are also efficient, in the sense that they take almost no time to set up and take down. Emergency bivy sacks are what you’ll want to have on hand when disaster strikes, making them ideal for hiking, mountaineering, or as a way to stay warm in the car.

In terms of insulation, many campers comment on how quickly they warm up inside of a bivy sack. The extra layers typically add about 8 more degrees to the temperature rating for your sleeping setup. That means, if your sleeping bag, sleeping pad, and liner can keep your comfortable down to 25 degrees, the addition of the bivy sack will typically keep you warm down to 17 degrees.

The Cons…

best bivy sack

Needless to say, I don’t recommend this product for people who suffer from claustrophobia. If you don’t mind tight spaces when you enter the sack, you might find yourself developing a fear after a few hours feeling trapped like a mummy with nothing but a few holes for your eyes and mouth. There won’t be any room to sit up, and rolling over during the night can be a struggle. I would not suggest getting a bivy sack if you expect this lack of space to cause problems for you – not even the best bivy sack is spacious enough to keep my anxiety levels down!

Also, good luck finding space to store your other gear. Lightweight bivy sacks will barely be big enough for you, so don’t expect to have any extra space to put your backpack, shoes, or other items that you might want to keep out of the elements and away from animals. This can be a deal breaker for some, but for others who were looking to be ultralightweight anyway, it’s not as big of an issue.

Bivy Sack Comparison Table

Bivy Sacks Comparison
Bivy SacksWeight (oz)MaterialSizeBest Use
Winterial Bivy Sack40Polyester90 x 38 x 28 InchesCamping, Hiking
Dibbatu Emergency Bivy Sack4Nylon83 x 35 InchesEmergency, Survival
GEERTOP Ultralight Bivy Tent64Polyester84 x 40 x 36 InchesBackpacking, Camping
Tact Bivvy 2.04.8HeatEcho84 x 36 InchesCamping, Survival
Black Diamond Big Wall Hooped Bivy Sack17ToddTex99 x 35 x 10 InchesClimbing, Big Wall
Outdoor Research Bug Bivy16No-See-Um Mesh89 x 25 inchesCamping, Insect Protection

Top Bivy Sacks – Reviewed

Winterial Bivy Sack

Winterial Single Person Personal Bivy Tent - Lightweight One Person Tent with Rainfly, 2lbs 9oz, Stakes, Poles and Guylines Included, Backpacking and Hiking Bivy Tent (Olive Green & Orange)
  • Weight: 2.5 Pounds
  • Material: Polyester
  • Size: 90″L x 38″W x 28″H

This bivy tent isn’t exactly the same as a sack, but they’re close enough where I feel comfortable putting it in this review. At 2 pounds, 9 ounces, it has a lot of the same features as a tent while cutting back on weight. There’s a full coverage rainfly that’s completely waterproof and helps keep you insulated in cooler temperatures – during the summer, feel free to remove the rainfly for excellent ventilation and a great view of the sky above.

It comes with 2 aluminum tent poles to help keep the fabric raised above your body. At its full height, you should be able to bend your knees upward without them brushing the ceiling, which helps alleviate any sense of claustrophobia you might have. The tent floor and rainfly are also sufficiently waterproof, giving you a durable shelter for one that you can take anywhere with minimal effort.

Reasons For

Hooped poles to help alleviate claustrophobia

Under 3 pounds

Durable and waterproof

Additional storage options inside

Reasons Against

Not exactly freestanding

Not really suitable for people over 6 feet tall

Dibbatu Emergency Bivy Sack

DIBBATU Emergency Survival Sleeping Bag, Thermal Bivy Sack Blanket, Waterproof Lightweight, Mylar Portable Nylon Sack for Camping Hiking Outdoor Adventure Activities and Help Homeless People
  • Weight: 4 Ounces
  • Material: Nylon
  • Size: 83″L x 35″W

More along the lines of what you’d expect out of a good bivy sack, Dibbatu made something that’s about as minimalist as you can get without sacrificing what you need. Essentially a waterproof bag, you could get away with using nothing more than this on hot summer nights when you’re trying to stay really lightweight. However, pairing it with a down sleeping bag (and maybe a camping pillow) is what I would recommend.

It’s a thermal, emergency bivy sack, which means it’ll reflect back a lot of your body heat. Because of how light they are, and how easily they pack down, they make for great survival shelters. For day hikes, or other outdoor excursions, I would recommend bringing one of these emergency bivy sacks in case something goes wrong, and you need the protection. They do smell a little funny, but that’s a small price to pay for a solid barrier between you and the elements.

Reasons For

Very light and minimalist

Convenient carry case

Surprisingly warm

Versatile and cheap shelter

Reasons Against

Smells funny

Protection isn’t as thorough as a bivy tent

GEERTOP Ultralight Bivy Tent

GEERTOP Ultralight Bivy Tent for 1 Person 3 Season Waterproof Single Person Backpacking Tent for Camping Hiking Backpack Travel Outdoor Survival Gear
  • Weight: 4 Pounds
  • Material: Polyester
  • Size: 83.85″L x 39.76″W x 35.82″H

Leaning toward the fancy side, GEERTOP’s lightweight bivy tent is a great option if you want a little more than just a thin bag to slide into at night. At just over 3 pounds, you’ll still be able to pack light without completely giving up on any semblance of comfort while camping.

It’s double layered (tent + rainfly), which helps you stay warm and insulated, while also making the shelter water resistant. Considering the two aluminum poles and small tent body are all you have to worry about, it doesn’t take very long to put together. Expect to have your shelter all ready to go in under 10 minutes – or under 5, if it’s not your first time doing it. And if you don’t like re-breathing the same air all night as your tent walls start to drip with condensation, you’ll enjoy the 2 windows and doors that come built into this structure. On comfortable summer nights, especially, there’s nothing better than letting the breeze come in while looking up at the stars.

Reasons For

Under 4 pounds

A bit more spacious than your typical bivy sack

Internal storage options

Waterproof tent floor and rainfly

Packs down small

Reasons Against

A bit tight for folks over 6 feet

Zippers aren’t the greatest

Tact Bivvy 2.0

Survival Frog Tact Bivvy 2.0 Emergency Sleeping Bag w/Stuff Sack, Carabiner, Survival Whistle, ParaTinder - Compact, Lightweight, Waterproof, Reusable, Thermal Bivy Sack Cover, Shelter Kit
  • Weight: 4.8 Ounces
  • Material: HeatEcho
  • Size: 84″L x 36″W

One of our final selections for this review, the Tact Bivvy 2.0 is a fairly impressive product. Made out of thermal polyester, it’ll reflect your body heat back at you in a constant effort to help you stay warm on cold nights. The material is tear proof, windproof, waterproof, and basically any other kind of “proof” you can think of, so durability will be the least of your concerns. It’s another great emergency bivy option, similar to the Dibbatu product mentioned above.

Like other bivy sacks, the Tact Bivvy is a lightweight shelter that will protect you in wet weather. Naturally, it doesn’t provide much in the way of comfort, but what else would you expect from a thin sack that only weighs 4.8 ounces? It’s not much, but it makes a big difference if you like to make a habit out of staying warm and dry. Feel free to use it with or without an actual sleeping bag inside. If you find yourself sleeping in the car, slip inside this sack to regulate your body temperature during the night. Since it’s the lightest bivy in our review, you can get pretty creative with how it’s used.

The drawstring can be used to tie down your gear, and the inside of it is a para-tinder cord. In case of emergency, when you need to build a fire, the cord can be used to get your blaze going.

Reasons For


Heat reflective

Drawstring can be used to start a fire


Versatile design: can be used as a tarp, sleeping bag, or ground sheet

Reasons Against

The condensation build-up is no joke. You’ll wake up wet.

Black Diamond Big Wall Hooped Bivy Sack

Black Diamond Big Wall Hooped Bivy Long
  • Weight: 1.1 Pounds
  • Material: ToddTex
  • Size: 99″ x 35″ x 10″

You might not think of bivy sacks when you hear the name “Black Diamond,” but here you have it – the BD Big Wall bivy. A frameless shelter, the Big Wall is very effective at minimizing your overall pack weight, which is one of the primary reasons why folks opt for a bivy shelter in the first place. Weighing just over a pound, it would make a great addition to any ultralight backpacker’s checklist.

That being said, this is a bivy sack designed for rock climbing – specifically, spending a night on a portaledge several hundred feet off the ground. Still, it gets the job done even when you aren’t anchored to the side of a cliff. Because it doesn’t have any structure to it, the sack does hug you like a mummy bag. If you struggle with claustrophobia at all, this might not be the product for you; however, if you value warmth and a minimalistic design, you’ll be hard pressed to find something better. Since it is a bit tighter, though, I’d suggest you keep your sleeping pad on the outside of the bivy, instead of shoving it inside with you and your sleeping bag.

Condensation buildup is pretty typical, even if you keep the hood open, and it’s not the best at protecting you against heavy rainstorms. However, this isn’t terribly surprising, considering it was created to be a lightweight option for you to carry during extreme backpacking.

Reasons For


Frameless design

Very minimalistic

Warm and comfortable

High quality

Reasons Against

Not for heavy rain

Outdoor Research Bug Bivy

  • Weight: 1 Pound
  • Material: Mesh
  • Size: 89″ x 25″

The Outdoor Research bug bivy is great for a select group of people, as you can probably tell based off the photo of the product. Though you’ll be fully enclosed, this lightweight bivy doesn’t have any weather resistance, making it a bad choice to bring to places known for inclement weather. This includes the mountains, and some coastal regions that are known for bad weather.

However, as long as you check the forecast beforehand, this bug net bivy sack is really fun to sleep in because of how exposed you’ll feel. The stars will be right above you, and ventilation won’t be an issue at all. On hot nights especially, you’ll be glad to feel the breeze coming through the no-see-um mesh covering. And with the overhead pole keeping the mesh away from your face, and the long zipper allowing for rapid entry, you’ll be able to enjoy a comfortable night in this bug bivy sack.

Reasons For

Only weighs a pound

Great for ventilation

No-see-um mesh keeps all the bugs out

Single pole to get the mesh (and bugs) away from your face

Long zipper for rapid entry

Overall, great for desert camping

Reasons Against

Not designed for rainy weather

Funky guylines

Why Trust US

At Untamed Space, we’re passionate about helping you have the best camping experience possible. Our team of experts have experience camping and backpacking all over the world, allowing them to provide insightful and relevant content to guide you in your outdoor pursuits.

All of our reviews are based on a combination of firsthand experience, extensive research, and an analysis of customer feedback. We are an independent website and do not receive payments or incentives from manufacturers to promote their products, and we continuously update our content to provide new information based on product availability. Wherever you are in your journey, whatever gear you’re searching for, you can be sure to find unbiased and up-to-date reviews for all of your needs.

Final Thoughts

This is the part where I usually give my final thoughts on the generally agreed upon winner by the Untamed Space team. And don’t get me wrong, I’m still going to do that, but I feel like I need to preface it with a minor disclaimer.

Bivy sacks are very personal, and some of the options we’ve listed are drastically different. Some are literal polyester bags that you can pull around you, while others more closely resemble what a tent should look like. There is no right or wrong answer, and what works best for you is entirely dependent on personal preference and the situation you find yourself in. With that in mind, we liked the GEERTOP ultralight bivy tent. I don’t know about you, but I’m not a huge fan of sleeping in a sack, so the two aluminum poles were a sight for sore eyes. Unfortunately, it is heavier than 5 ounces, but I don’t think that’s a deal breaker for most of you. For reduced weight backpacking, you’re still going to love this bivy tent, and the barrier it creates between you and nature.

Meet the Author!

By the age of 20, Spencer had already tackled some of the most famed mountain ranges in Europe, Asia, and North America. His mission is to help others accomplish their own outdoor-related goals, even within the time constraints of a 9-5 job and a busy life schedule.

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