A guide to bivy sacks for ultralight backpacking. Considerations, tips, and best models.
© Andrew McCartney (@amactriguy)
When you want protection from the elements but don't want to carry a tent, then you should seriously consider a bivy sack (also spelled "bivvy" or "bivi"). Think of a bivy sack as a rain jacket "shell" for you and your sleeping bag. It fits over your sleeping bag covering your from head to toe and protecting you from rain, wind, and bugs.
A bivy sack doesn't have multiple poles or even a rain fly, so it often is lighter and significantly smaller than a tent. Most bivvies have just enough room for you to climb into your sleeping bag and get comfortable. Not everyone likes the closed-in comfort of a bivy sack. We run down what you need to consider before you purchase a bivy and share some recommendations if you want to embrace this tent-free way of backpacking.
There are three main types of bivy sacks - traditional sacks, face lifters, and bug nets. They all share a similar "slip over your sleeping bag" design, but they differ in weight, comfort, and purpose.
Sacks: Traditional sacks fit over your sleeping bag, covering it from head to toe. There is a flap with a zipper at your head that you can leave open on a warm, dry night. Or, close it shut when the weather is nasty. When you close this flap, you are completely sealed into the bivy sack much like a coffin. You should leave a small opening in the zipper so you can let some fresh air into the bivy sack and allow condensation from your breathing out.
Face-Lifters: Face-lifters enclose your sleeping bag like a traditional bivy sack, but these sacks have a hoop at the head for comfort. This minimizes the coffin feel of a bivy sack while keeping the weight and size advantages. The hoop gives you some room to read or check your phone before you crash for the night.
Bug Nets: Sometimes, all you need is a simple bug net to keep the insects at bay while you sleep. These bug net bivy sacks enclose your sleeping bag in a fine mesh fabric that won't let through even the smallest no-see-um. They often have a hoop or a pole in the head area so you won't get bit through the fabric.
Bivvies may be small, but they are a versatile shelter. Because they are compact and lightweight, you can carry them on hikes where a tent is an overkill.
Emergency shelter: You can carry a bivy when you don't need a tent and just want a backup plan. I used a bivy once when a day hike suddenly became on overnighter because of an injury.
Cowboy camping: Bivy sacks are great for cowboy camping, especially in a dry and moderately hot climate. You get some protection from the elements without obstructing your view of the sky.
Main Shelter: You can save a pound of pack weight with a bivy sack, just be sure you feel comfortable sleeping in a small, almost coffin-like setup.
© Marlin Thorman (@thormanclimbing)
WEIGHT: Bivy sacks tend to be lightweight but each additional feature, like a hooped pole or an extra set of zippers, adds to the weight. Keep your bivy sack as close to (if not under) a pound as possible. As you start inching above a pound, you should look at an ultralight shelter. Ultralight tents weigh around 2 pounds and offer significantly more comfort than a bivy sack.
PROTECTION: A bivy sack's primary purpose is to protect you from the elements. A good bivy sack will have a waterproof floor and top as well as pre-taped seams to protect you from the rain. It also should have ample zippers or a hoop opening for extra ventilation.
SPACE: Bivy sacks are limited on space by design. Some manufacturers add a hooped pole at the head for some extra room, but many don't. If your bivy lacks a hoop, be prepared to sleep with the fabric resting on your face at night.
Face-lifters offer considerably more space than sacks.
MATERIALS: Just like rain jackets, bivy sacks use a variety of waterproof and breathable fabrics. You'll see GORE-TEX, ToddTex, Pertex, eVent.
ZIPPERS: All bivys have a zipper that allows you to climb into the sack. Some zippers open along the center of the bivy sack, while others zip on the side. Both are equally useful, just make the zippers are long enough that you can get quickly in and out of the sack. Avoid bivys that have short zippers that require you to shimmy your way into the sleeping system.
FEATURES: Bivy sacks are pretty basic, but they do have a few amenities. Some include a bug net so you can leave the outer flap open for breathing, while others have a window that allows you to see outside when the flap is zippered tight. Other features include internal pockets for storing a headlamp or glasses, straps for holding a sleeping pad, or antifungal flooring to prevent mold.
A bug net allows you to leave the flap of the bivy open for better breathability (and star-gazing).
Whether you need a bivy for emergency situation or want a no-fuss shelter for climbing Denali, there is a bivy sack to meet your needs. We’ve hand-picked the best bivys available so you can spend less time researching and more time exploring the great outdoors.
Length: 79 inches to 93 inches
Width: 76 inches to 88 inches
Weight: 7.2 ounces to 9.7 ounces
Material: Pertex Quantum shell, 30D double-coated Cordura Silnylon floor
Price: $155 to $165 at Katabatic
Colorado-based Katabatic Gear is known for its top-notch ultralight sleeping bags, but the company has expanded to include bivys, backpacks and more. All its gear is made in the USA with almost all the manufacturing handled in-house. The quality of this craftsmanship and design is evident in the company's Bristlecone Bivy.
The Bristlecone is one of the lightest bivy sacks on our list, weighing a mere 7.5 ounces for a standard-sized sack. Even though it is light, you don't have to sacrifice quality or features. The Bristlecone has a sil-nylon bathtub floor for added protection from the rain and a DWR Pertex top shell that is breathable and waterproof. Other niceties include a hang loop to keep the bivy off your face, straps to hold your sleeping pad in place, and a small bug net window that lets you breathe without getting bit.
Unlike most bivys that require you to shimmy into the sack, the Bristlecone has a three-quarter length YKK zipper that makes it easy to climb in and out of your sack. You can choose between a left-sided or right-sided zipper when you are making your purchase.
Length: 88 inches
Weight: 12 ounces
Material: 20D ripstop nylon 2 ply breathable 1000mm top shell, 15D ripstop nylon 1200mm Xtreme Shield floor
Price: $200 at MSR
MSR's Pro bivy replaces the All Conditions bivy in MSR's lineup and serves as minimalist bivy that is one step up from an emergency bivy. Designed for fast pack alpine pursuits, the Pro is lighter and more packable than its predecessor. It doesn't have the bells and whistles of other bivy sacks - there is no zipper or bug netting. The only distinguishing feature is a simple flap that opens and allows you to shimmy into the sac.
It may not be fancy, but the MSR Pro is a reliable bivy for emergency situations or minimalist camping. Like most bivys, the small footprint allows you to pitch the Pro in areas too small for a tent. It is waterproof enough to keep you dry in the light rain and durable for regular use. And at less than a pound, you won’t mind throwing this bivy into your pack for those “just in case” situations or even a quick overnight.
Length: 92.5 inches
Width: 31.5 inches
Height: 11.8 inches
Weight: 16.5 ounces
Material:15D eVent® DVStorm 3L fabric top shell; 70D nylon floor
Price: $275 at Moosejaw
The Rab Alpine Bivy may not be the most-feature rich bivy on our list, but it excels where it matters the most - wind and water protection. When the weather gets rough in the alpine zone, the fully-enclosed design of the Rab Alpine bivy keeps you shielded from the snow and protected from the wind. You can open the zipper just enough for a breeze to circulate the air inside the bivy sack, but not so much that you allow snow or sleet to blow into the sack. The bathtub floor provides ample protection from melting snowpack and snowdrifts.
Because it is designed for alpine pursuits, the Rab Alpine is best suited for cold, windy and snowy weather. It doesn't perform as well in warm and wet climates because it doesn't have mesh or a face-lifter for ventilation. It's a minimalist bivy that is comfortable enough for short ventures but may not be adequate for weeks in the backcountry.
Length: 80 to 86 inches
Width: 36 to 40 inches
Weight: 14-16 ounces
Material: 20D Nylon Ripstop DWR, 30D Nylon Ripstop DWR
Price: $140 at Moosejaw
Sierra Designs nails it with its Backcountry Bivy, a three-season bivy that can replace a tent if you are looking to lighten your weight without sacrificing comfort. Not only is the Backcountry Bivy roomy for a bivy sack, but it also is lightweight and compact, squishing down to the size of a Nalgene bottle. Best of all, its affordable price tag makes it easy to recommend for those looking for a solid-performing bivy sack.
Feature-wise, the bivy sack has a U-shaped zipper that makes it easy to get in and out of the portable shelter. A mesh panel at the head provides ventilation and protection from biting insects. There's even an attachment point at the head that you can use to lift the mesh off your face and provide extra room if desired.
For its weight, the Sierra Designs Backcountry Bivy offers excellent protection from wind and rain. The waterproof and breathable top keeps you dry on the inside and out, while the bathtub bottom prevents splashes from entering the sack. You just have to be careful with the zippers which are covered with a storm flap but are not waterproof. You may get some leaking if the wind is powerful enough to lift the flap and the rain is heavy enough to saturate the zipper fabric.
Length: 82 inches
Width: 26 inches
Weight: 16.2 ounces
Material: 2.5-layer Pertex Shield with 30D ripstop nylon top shell; 40D nylon with TPU lamination floor
Price: $180 at Outdoor Research
The Outdoor Research Helium bivy is one of the most popular bivy sacks and for a good reason. It strikes a near perfect balance between weight, weather protection, comfort and price. Backpackers looking for a lightweight alternative to a tent can't go wrong with the Helium. It’s that good.
The Helium is lightweight and compact in your pack, yet roomy when you need to climb into the bivy at night. It has plenty of headspace with room enough for an inflatable pillow if you so desire. The head area is a combination of mesh and waterproof nylon that you can zipper shut during inclement weather and open to provide ventilation on balmy evenings. When you batten down the hatches, the waterproof and breathable Pertex Shield fabric keeps the rain on the outside where it belongs and minimizes condensation on the inside. It’s ideal for three-season use and can handle some winter weather if needed. . If you need a shelter for winter use, then look at the OR Alpine bivy which shares the same design as the Helium, but is made with more rugged material.
Length: 82 inches
Width: 26 inches
Height: 20 inches
Weight: 20.6 ounces
Material: 30D nylon ripstop with GORE-TEX® Respiration Positive™ 3L upper; 40D ripstop with TPU lamination floor
Price: $250 at Outdoor Research
The Outdoor Research Alpine Bivy takes the successful design of the company's Helium bivy and beefs it up for the extreme weather of alpine pursuits. It is constructed with a rugged 40D ripstop floor and a 30D nylon upper with 3L Gore-Tex respiration positive fabric for waterproofing and breathability. This winning combination of Gore-Tex and nylon ensures you'll stay dry in the rain and the snow without worrying about condensation.
Similar to the Helium bivy, the Alpine bivy has a pole for headspace and a mesh netting for ventilation. When the weather is rough, the overlapping zipper allows you to keep the sack open slightly for ventilation while preventing snow and rain from seeping inside the sack. If you need a bombproof bivy for winter expeditions, look no further than the Alpine bivy from Outdoor Research.
Length: 107.87 inches
Width: 41 inches
Height: 27 inches
Weight: 18 ounces
Material: 10D Sil/polyurethane ripstop nylon/ with no-see-um- mesh top shell, 15D Sil/polyurethane ripstop nylon floor
Price: $450 at Moosejaw
Nemo's Gogo Elite Bivy is a full-fledged bivy sack that can replace your tent in a heartbeat. The sack sets itself apart with its Air Supported Technology that uses an air-filled chamber instead of poles in the bivy. Unlike poles that can break, these air chambers won’t add extra weight and, best of all, won't fail when the wind picks up. Because there are no poles to fuss with, the Gogo Elite is incredibly easy to set up - just blow a few puffs of air into the bivy, and you are ready to go.
Some bivys feel like you are sleeping in a coffin, but not the Gogo Elite from Nemo. The Gogo Elite has a unique design that gives the bivy a tent-like feel without the extra weight of a tent. There is plenty of headroom at the top and room enough to shift positions while you sleep. It even has a small vestibule for gear storage and a swallowtail foot that provides extra room without using stakes. It is longer and taller than most other bivy sacks on the market. Despite its roominess, the Gogo Elite is super compact, packing down to the size of a jetboil canister stove.
Length: 89 inches
Width: 25 inches
Weight: 16 ounces
Material: 100% polyester mesh top shell, two-layer nylon plain weave taffeta floor
Price: $90 at Outdoor Research
Most people agree that Outdoor Research is the king of bivy sacks. Not only does the company make the outstanding Helium bivy and the rugged Alpine bivy, but it also makes a bug net bivy. The bug net bivy is perfect for warm and dry climates where bugs are more of a nuisance than rain or wind. Because it is made from mesh, there is no problem with condensation, but you may want to carry a tarp in case you encounter wind or rain.
The OR Bug bivy uses the same design as the Helium and the Alpine but takes away the nylon top of the bivy and replaces it with a bug net. A well-placed pole at the head with a stake out point keeps the netting off your face, while a stake out point at the foot keeps it suspended off your body. With the mesh away from your body, your chance of getting bit is slim. Not only is the bug bivy fantastic for keeping the bugs at bay so you can sleep peacefully under the stars, it also keeps out critters like mice and snakes.
Length: 82 to 87 inches
Width: 76 to 83 inches
Height: 18 inches
Weight: 6.35 ounces
Material: 10D nylon and mesh top shell, 15D waterproof silnylon floor
Price: $150 at Enlightened Equipment
Designed and made in Winona, MN, the Enlightened Equipment (EE) Recon takes the best of a three-season bivy sack and adds enough mesh that it almost qualifies as a bug net bivy sack. The recon has a 5.5-inch bathtub floor made with 15D waterproof silnylon that is topped with DWR-treated nylon. A long no-see-um mesh panel cover your head and torso, providing excellent ventilation and protection from biting insects. It is ultralight thanks to its lightweight nylon fabric and mesh exterior. Though it could replace a tent for longer excursions, the minimalist Recon is best suited for short overnights in warmer weather.
The EE Recon is not as easy to use as other minimalist bivys like MSR Pro. Though you can just climb into the bivy and crash, you really should spend a few minutes staking and suspending the Recon if you want full protection from the elements and insects. The Recon has two shock cords - one at the head and one at the foot - that lift the bivy off your body and provide extra room. There also are four corner stake loops to maximize space and help the bivy keep its rectangular shape. Because of its unique mesh design, the Recon works best when paired with a tarp for protection from the wind and rain.
Dimension: 87 inches long
Weight: 22 ounces
Material: Pertex nylon top shell and waterproof, abrasion-resistant ripstop nylon floor
Price: $150 at REI
REI's Superlight bivy is one of the most comfortable bivys available thanks to its boxy design that provides ample room in the headspace and foot box. There is plenty of room for a sleeping pad, sleeping bag, your boots and even a pillow. To get this extra room though, you have to stake out the four corners of the bivy and use the pole at the head of the sack.
This extra room has another benefit - ventilation. The extra space inside the bivy lets air circulate throughout the sack and helps remove moisture before it condenses on the inside. The zipper plays an important role in this ventilation - it has a unique design that allows you to open it slightly without letting in the rain or wind. Even in the wettest conditions, condensation is not a problem with the REI Superlight.
Similar to other bivys on our list, the REI Superlight uses a Pertex nylon shell that provides ample protection from the rain, wind and light snow. An added storm flap protects the zippers under most conditions. In heavy winds, though, the flap can blow open exposing the zippers to rain and snow. As a consolation the zippers let in very little moisture even when exposed. The Superlight is geared toward three-season use and compares favorably to the OR Helium bivy.
Length: 84 inches
Width: 31 inches
Weight: 8.5 ounces
Material: Metalized spun-bonded olefin
Price: $70 at REI
A true emergency bivy, the SOL Escape bivy is a remarkably simple and effective bivy sack for an unexpected night outside. It is constructed with a proprietary fabric that is both water-resistant and breathable, so even if you are forced to spend the night outside, you will still be comfortable. An internal reflective layer helps keep you warm down to 50-degrees when you don't have a sleeping bag. A zipper makes it easy to get in and out of the sack with minimal shimmying.
The SOL Escape is not designed to be a tent replacement, but it can be used multiple times as long as you handle it gently. Because it is so light, some people even use it to add 6 to 8-degrees of extra warmth to a sleeping bag. And with a sub-$100 price tag, the SOL Escape is a must-have if you are on a budget and want to carry some extra protection in case you are forced to spend a night outside.
Most people choose a bivy sack because they don't want to lug around a tent. There are definitely some benefits to using a bivy sack, but there are also some negatives. We break down the pros and cons of choosing a bivy sack over a tent.
✅ Weight: Bivy sacks are lighter than tents, making them an attractive choice for backpackers who want to go as lightweight as possible.
✅ Packability: Bivy sacks pack smaller than tents, so they take up less space in your pack. Less space for your shelter means you have more space for other essentials such as food and water.
✅ Ease of use: Bivy sacks are easier to set up than a tent. Except for face lifters, there are no poles and no stakes with a bivy. You lay it on the ground and climb in it. Face lifters include a single hoop that requires a few stakes to hold it in place.
❌ Breathability: Condensation can be a big issue with bivys. The water vapor from breathing and sweat from sleeping can condense on the interior of the bivy sack. Because a bivy is single-walled, this moisture accumulates right next to your sleeping bag, potentially soaking it with water as you sleep. Most tents minimize condensation because of their double-walled design. A tent allows the water vapor to travel through the mesh canopy and collect on the outer rain fly far away from your sleeping bag and personal belonging.
❌ Space: Bivys are much smaller than tents and only suitable for sleeping. There is no vestibule to store your shoes or gear. You also can't change clothes or cook inside a bivy. And worst of all, you are stuck in a tight space on bad-weather days.
❌ Protection: It's debatable whether a bivy sack provides extra protection from the weather than a tent. A bivy sack can be warmer than a tent because less air around you to heat, but you are in close contact with the outside elements. Cold snow and wet rain can fall right on top of you. There is no rainfly to shed snow and keep the rain at a distance.
How to care for a bivy sack?
Clean a bivy sack like you clean your rain jacket. Use water to spot clean. Follow the instructions on the sack, but in general, you want to use a gentle cycle, warm water, and a cleaner like Nikwax Tech Wash, which is designed for waterproof fabrics. Do not use regular detergents, fabric softeners, or bleach. Allow the bivy to air dry or throw it into a dryer for 20-30 minutes on a warm, gentle cycle.
How to pack a bivy sack in your backpack?
Pack a bivy sack just like you'd pack a tent. Stuff it into a waterproof stuff sack to keep it dry while hiking. If it is wet, a waterproof sack will keep the rest of your pack contents dry until you can find a sunny spot to dry your bivy.
How to waterproof a bivy sack (and should you)?
Most bivy sacks are made with waterproof fabrics, but this waterproofing does not always last. You can and should waterproof a bivy to help repel the rain. Choose a compatible DWR product like Nikwax TX Direct Spray-On Water-Repellent Treatment and add a sealant to the seams.
By Kelly Hodgkins: Kelly is a full-time backpacking guru. She can be found on New Hampshire and Maine trails, leading group backpacking trips, trail running or alpine skiing.
About Greenbelly: After thru-hiking the Appalachian Trail, Chris Cage created Greenbelly to provide fast, filling and balanced meals to backpackers. Chris also wrote How to Hike the Appalachian Trail.
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