No matter what type of outdoor adventure you’re embarking upon, a shelter is a critical component of your gear list. Although a standard backpacking setup typically includes a tent, there are times when a full shelter is overkill. Maybe you’re heading out for a fast-and-light trip and each ounce in your pack is at a premium. Or perhaps you need a backup shelter that just weighs a few ounces to throw into your day-hiking pack in case of emergency.
In my years of backpacking, peak bagging, and base camping, I’ve spent time in every sort of shelter, from ultra-spacious to minimalist. A bivy, short for bivouac, is a minimalist shelter, especially when compared to a tent. It protects one person from bugs, wind, or rain in the form of a single-person tent or a water-resistant sack, often used in addition to your sleep system. Pair yours with a waterproof tarp for extra protection or use it on its own in dry conditions.
Who is a Bivy Sack Best For? How Are They Used?
Bivies are a great option for people who are new to backpacking or mountaineering and want something relatively inexpensive with a small footprint. They also work well for ultralight fastpackers with a minimalist setup or anyone traveling in the backcountry who doesn’t want to carry a full tent.
A bivy hits the sweet spot between cowboy camping and carrying a full shelter—they pack down small, and they can function as a long-term shelter for extended trips or an emergency shelter to keep in your car or survival bag. Some bivies can be used on their own during warm nights, or you can put your sleeping bag inside for added protection from the elements. A bivy sack will add up to 15 degrees of warmth to a sleep system, and putting your sleeping pad inside the bivy helps prevent sliding.
Bivy Sack Styles
There are a few main styles of bivy sacks. Some have an internal pole structure and are pitched with a set of ultralight poles that create a dome or pyramid over your head for added space. These are the closest style to a one-person tent and have space for gear, albeit with a smaller footprint, less headroom, and lower weight than many classic solo shelters. This style is best for backpackers looking for a lightweight, no-nonsense one-person shelter that can pitch pretty much anywhere.
The minimalist bivy is the style you might be more familiar with. It looks similar to a sleeping bag with some closure options around your face. These hold a sleeping bag and pad and usually sport a waterproof or durable water repellent–treated shell. These are for fastpackers who need little to no extra space in their shelter and are sometimes used by record-setting hikers going after FKTs.
Lastly, there are emergency bivies, which use a heat-reflective aluminium-covered fabric and function as heavy-duty emergency blankets with enclosed coverage. These are best to keep on hand during a long summit day in case of bad weather or as part of your emergency kit.
What to Consider When Choosing a Bivy Sack
Start with materials and waterproofing. Does your destination or trek get a lot of rain? You’ll want something fully waterproofed with taped seams. Low chance of rain or snow? You might get away with a DWR treatment on the face fabric, but it’s not a bad idea to have an additional tarp. Desert trip? A bug bivy with mesh walls might be all you need.
Next, consider livability and size. A bivy is smaller and more compact than other types of shelters, but they are fully enclosed. Some have full-length side zippers that are easier to get in and out of compared to top-entry models. However, a top-entry bivy seals out drafts better.
Look at a model’s dimensions and pole structure (if any) and make sure it’s large enough to comfortably sleep in while not being so big you have trouble keeping it warm. Below, we list the dimensions of each bivy’s length and widest point (at the shoulders), but keep in mind that most taper towards the feet. Some also have more lofted headroom than others.
How We Selected
I dove headfirst into backcountry travel when I moved out West over a decade ago. Since then, I’ve backpacked thousands of miles around the country in all four seasons. I’ve helped develop desert routes, thru-hiked the Appalachian Trail, and solo hiked the 500-mile Colorado Trail. I’ve been reviewing and testing gear professionally for the past seven years, working with REI, The Strategist, The Trek, Backpacking Light, Thrillist, and Backpacker. I co-founded BackpackingRoutes.com in an effort to make aggregated trail information more accessible and reliable for trails of all distances and types. I’ve spent a lot of time in the backcountry and used a lot of different gear.
To find the best bivy sacks, I considered the primary styles, then picked the top models from each category. I took into consideration the different reasons for carrying a bivy—emergency shelter versus daily use while trekking—to help inform our choices and find something to fit every need. These recommendations come directly from my experience as well as other avid backpackers and mountaineers who use bivy sacks as shelter for long-distance hikes.
- Weight: 1 lb. 0.5 oz.
- Dimensions: 92.5 x 31.5 in.
- Style: Minimalist
This is a highly durable and compact bivy that can take the place of a one-person shelter for true minimalist backcountry travelers. Although this shelter does weigh about as much as some ultralight tarp-tents, you get the benefit of a narrow footprint that can fit pretty much anywhere, as well as less space to be hit by wind. The Alpine Bivi packs down to the size of a water bottle, has an eVent membrane for maximum waterproofing and breathability, and a durable nylon floor so you don’t have to worry about tears or punctures on rocky or rough campsites. The entrance zips open and has storm flaps for more protection—ideal for alpine ascents or an emergency shelter for harsh conditions above treeline.
- Waterproof, breathable membrane
- Highly weatherproof
- Relatively heavy
- Weight: 1 lb. 13 oz.
- Dimensions: 92 x 30 in.
- Style: Pole structure
The Bipod is among the pricier options, but for mountaineers, it’s one of the best bivy shelters out there. The alpine-ready shelter provides protection during all four seasons, thanks in part to the ToddTex single-wall fabric that has fully taped seams and a waterproof, breathable membrane. The smaller spaces of a bivy are prone to condensation from your breath, but the Bipod has some of the best performances when it comes to reducing overnight condensation due to its mesh door panels. The lightweight aluminum pole with the shock cord gives ample head and shoulder room inside—just be careful to not overextend the shock cord to preserve its lifespan. We love the zippered entry and option to leave the mesh door panels open for added ventilation on clear nights. You’ll be carrying more weight with this bivy, but the protection, space, and four-season capabilities are worth it.
- Spacious interior
- Waterproof and breathable
- Heavy for a bivy
- Weight: 1 lb.
- Dimensions: 89 x 25 in.
- Style: Pole structure
This is the only bivy on the list without any sort of protection from precipitation, but for bugs and ventilation? Can’t be beat. It’s made with ultra-fine netting to keep even the tiniest bugs out, and we love the generous 50-inch girth of the U-shaped Delrin pole that keeps the mesh away from your face. It has a raised foot area that can be tensioned with tie-outs, so you can stash gear inside and keep the material off the bottom of your legs. We like using the tie-outs to maximize space, but they aren’t necessary for the structure. This bivy comes with straps to prevent your sleeping pad from sliding and a wide zippered opening along the top. For rainy expeditions, pair it with a pole-and-tarp system.
- Foot area hits feet without being tied out
- Narrow shoulder width
- Not best for all-season use
- Weight: 7 oz.
- Dimensions: Sleeps people up to 6-foot-2
- Style: Minimalist
This ultralight bivy has been around in some iteration since its release in 2004. With a net-covered face window, a high-loft build that won’t compress your sleeping bag, and a surprisingly spacious design, the Superlight Solo hits the sweet spot for ultralight fastpackers who want some protection but don’t need a fully waterproof bivy or the space of a tent. This shelter was used by Joe “Stringbean” McConaughy for the duration of his Appalachian Trail self-supported speed record a few years ago and continues to be a favorite with ultralight backpackers. DWR treatment on the face fabric comes standard, but you have some wiggle room with materials and size. Mountain Laurel Designs offers several customization options including the option for an upgraded Dyneema floor.
- Very light
- Mesh face opening
- Custom options available
- Not waterproof
- Can be a long lead time between order and delivery
- Ultralight construction can be fragile
- Weight: 7 oz.
- Dimensions: 88 x 36 in.
- Style: Minimalist
Best used as an emergency shelter—or for extreme ultralight backpackers and mountaineers—this is a pared-down shelter without a zipper, bug mesh, or any bells and whistles. Still, the E-Bivy adds a few degrees of warmth to your system and blocks wind and precipitation to a certain point. The water-resistant top fabric—a 15-denier ripstop nylon coated in silicone—is paired with a fully waterproof Xtreme Shield floor. This bivy truly is minimalist, with an opening like an envelope that means you won’t be fully zipped up. Keep it stashed in your emergency gear, or carry it as a backup plan when you aren’t 100 percent sure if a trail will have open shelters.
- Waterproof floor
- Not best for extended use
- Top isn’t waterproof
- Weight: 14 oz.
- Dimensions: 80 x 36 in.
- Style: Minimalist
Constructed with a rugged 20-denier nylon ripstop, this brightly colored bivy was made to fit the Sierra Designs’ Backcountry Bed—their unique combination of sleeping bag and quilt. The spacious yet minimalist design also comfortably fits most inflatable sleeping pads along with other sleeping bags. This sack has a large top opening for easy in and out without the weight penalty of a full-length zipper. The mesh bug window keeps the crawlies off your face at night. However, in our experience, this is one of the less breathable bivy sacks on the list, and your sleeping bag might feel damp in the morning when camping in areas with a higher dew point. The material isn’t fully waterproof either, so bring a tarp or other additional shelter for nights with a wet forecast.
- Large top opening for convenient entry and exit
- Spacious shoulder and foot space
- Fits a sleeping bag and pad comfortably
- Collects condensation
- Not fully waterproof
- Weight: 8 oz.
- Dimensions: 100 x 34 in.
- Style: Minimalist
Rab is a company with deep roots in the alpine and mountaineering world, and the Survival Zone Lite is designed for those times when you wind up in poor weather or spending the night outside unexpectedly. Built with an ultralight wind- and water-resistant Pertex Endurance fabric, this bivy is a tear-proof shelter that you can use on its own or paired with a sleeping bag or other insulation. This has a drawcord top entry and is the longest bivy on our list, which means most people will be able to stash gear at their feet to protect it from the elements.
- Durable face fabric
- Not fully waterproof or enclosed
- Expensive for an emergency shelter
- Weight: 3.8 oz.
- Dimensions: 86 x 34 in.
- Style: Emergency
One of the best things about bivies is the ability to carry a fully enclosed emergency shelter, and with this model is a true emergency option. Because this bivy packs down to the size of a standard soda can and weighs under 4 ounces, the benefits of carrying it far surpass the added pack weight. Stash it in your day pack or general outdoor gear bag. We even recommend keeping one in your car in the winter. The aluminum-coated fabric reflects 90 percent of your body heat when deployed. It’s built with water- and windproof material for surviving an unexpected night out in the elements, and unlike mylar emergency blankets, the enclosed design blocks drafts and is reusable, stuffing back into its own carry pouch.
- Easily stashed for emergencies
- Not versatile or best for long-term usage