REI Co-op Magma 30 Sleeping Bag Review
A three-season backpacking and camping sleeping bag that comes in nine size options
October 15th, 2026
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Our verdict
REI Co-op’s Magma 30 is a great all-around bag for three-season backpackers and campers with nine size options.
The size range of nine options means there is something for backpackers of varying heights and widths and fills gaps in size inclusivity that have long existed for consumers who need bags outside of a “standard size.” The size inclusivity doesn’t compromise on performance, and the Magma 30 has a solid warmth-to-weight ratio and is surprisingly packable despite being slightly bulky. With high-quality 850-fill-power down and a silky exterior, and for just 1 lb 10 oz in the Regular Wide, the Magma 30 is both true to its temperature rating and durable despite how soft it is.
I first tested the Magma 30 in 2024, and have used it as my primary backpacking sleeping bag since then on over 24 nights backpacking and over 25 nights car camping during weeklong road trips where we car camped and/or backpacked.
Having a bag as light and cozy as the Magma 30 that fit me comfortably as a size 20/22/3X in clothing came in clutch on many trips. I’m a side sleeper, and generally wear plus sizes in my clothing and use wide width sizes of items like sleeping pads when they’re available. For many years, high-quality bags made for overnight backpacking were nearly impossible to find in wide sizes, and I hiked with a synthetic men’s bag that barely fit.
REI Co-op Magma 30
REI Co-op made the first bag I ever purchased in a wide size (the now discontinued REI Co-op Joule) and REI Co-op’s commitment to making strides in size inclusivity continues now with the Magma 30. The size inclusivity has allowed me to more comfortably sleep overnight while backpacking without lugging around something heavy or made of lower quality materials.
The Magma 30 is also easy to maintain and keep clean, and is more approachable in price when compared to other high-end bags of similar weight and fill power. The price, wide size range, high-end quality materials, and no-frills comfort makes it an ideal choice for many campers and backpackers, and our best affordable pick in our Best Backpacking Sleeping Bags guide.
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REI Co-op Magma 30 specifications
All Magma Sleeping Bag variants
Shape: Mummy
Fill: 850–fill water-resistant goose down (Bluesign approved)
Shell: 15-denier recycled ripstop nylon (Bluesign approved)
Lining: 15-denier recycled ripstop nylon (Bluesign approved)
Zipper location: Left
2-way side zipper: Yes
Draft collar: No (has an insulated yoke)
Draft tube: Yes (along entry zipper)
Hood: Yes, cinchable, with 2 differentiated drawcords for adjustment
Interior pocket: Yes
Stuff sack included: Yes
Storage sack included: Yes
Sustainability: Shell and liner made from recycled nylon that meets bluesign criteria, from a Climate Label Certified brand
Magma 30°F / -1°C
| Price | Comfort Rating | Lower Rating | Total Weight | Fill Weight | Shoulder Girth | Stuff Sack | Fits To | |
|---|---|---|---|---|---|---|---|---|
| Short Narrow | $349 | 34°F | 24°F | 1 lb 5.6 oz | 10.8 oz | 54 in | 6 x 14 in | 65 in |
| Short | $349 | 34°F | 24°F | 1 lb 6.8 oz | 11.5 oz | 61.5 in | 6 x 14 in | 65 in |
| Short Wide | $349 | 34°F | 24°F | 1 lb 8.4 oz | 12.4 oz | 69 in | 6 x 14 in | 65 in |
| Medium | $349 | 34°F | 24°F | 1 lb 8.4 oz | 12.7 oz | 62.5 in | 7 x 15 in | 71 in |
| Medium Wide | $349 | 34°F | 24°F | 1 lb 10 oz | 13.7 oz | 70 in | 7 x 15 in | 71 in |
Magma 15°F / -9°C
| Price | Comfort Rating | Lower Rating | Total Weight | Fill Weight | Shoulder Girth | Stuff Sack | Fits To | |
|---|---|---|---|---|---|---|---|---|
| Short Narrow | $399 | 21°F | 9°F | Not listed | Not listed | 54 in | 7.8 x 16.5 in | 65 in |
| Short | $399 | 21°F | 9°F | 2 lb 1.9 oz | 1 lb 4.9 oz | 61.5 in | 7.8 x 16.5 in | 65 in |
| Short Wide | $399 | 21°F | 9°F | 2 lb 3.6 oz | 1 lb 6.7 oz | 69 in | 7.8 x 16.5 in | 65 in |
| Medium Narrow | $399 | 21°F | 9°F | Not listed | Not listed | Not listed | 7.8 x 16.5 in | 71 in |
| Medium | $399 | 21°F | 9°F | 2 lb 3.6 oz | 1 lb 7.3 oz | 62.5 in | 7.8 x 16.5 in | 71 in |
Comparison table
| SLEEPING BAG | TEMP | SHAPE | INSULATION | WEIGHT | PACKED SIZE | MSRP |
|---|---|---|---|---|---|---|
| REI Co-op Magma 30 | 30°F | Mummy | 850 fill down | 1 lb 10 oz | 7 x 15 in | $349-359 |
| Therm-a-Rest Boost 650 | 20°F | Semi-rectangular | 650 fill down | 3 lb 5 oz | 20 x 7.5 in | $360 |
| NEMO Disco 30 Endless Promise - Men's | 30°F | Semi-rectangular | 650 fill down | 2 lb 1 oz | 7 x 10.5 in | $280-300 |
| NEMO Disco 30 Endless Promise - Women's | 30°F | Semi-rectangular | 650 fill down | 2 lbs 6 oz | 8 x 10.5 in | $280-300 |
Best for
Three season campers and backpackers looking for a bag with premium performance and features at a relatively approachable price point
Backpackers looking for a wider size range for varying body sizes and sleep styles.
Backpackers who prefer traditional mummy style bags but may want slightly more room or who have wider shoulders.
What we liked
The warmth-to-weight is pretty great especially when considering the price. The 850-fill water resistant goose down is lofty and efficient at warmth retention, while the 1 lb 10 oz weight in the Regular Wide is fairly light—especially for a bag that comes in wider sizes.
Nine size options for a bag of this performance and quality is unheard of across any other sleeping bag offered on the market right now. The genderless sizing does not assume gendered fit and instead is made for a wide variety of body shapes and heights, as well as types of sleepers who benefit from extra space for movement.
Value for the price: most higher-end backpacking sleeping bags with similar 850-fill power down cost hundreds of dollars more
What could be better
The Magma 30, while light enough for many backpackers, is bulky, and can take up a lot of space in your pack when not in a compression sack.(For example, I fit it in the sleeping bag compartment of my Gregory Kalmia 60 L (now discontinued), but it took up a significant amount of space in my Gregory Amber 44 L pack.)
The Magma 30 lacks some of the premium features found in bags like the Therm-a-Rest Boost 650 or the NEMO Disco Endless Promise, such as arm holes, chest vents to manage temperature control, and a draft collar–though these features do add weight so for some this could be a positive. It's more of a minimalist bag for gram-counting backpackers.
How we tested
I first used the REI Co-op Magma 30 in 2024, and have car-camped and backpacked with it extensively over the past two years. I often take trips where I both car camp and then backpack, often car camping after the backpacking trip has ended, and I appreciate the versatility of the Magma 30 for both settings. I have slept in the REI Magma 30 in my REI Basecamp 4 tent, in my Big Agnes Blacktail 3 tent that I take backpacking along with my partner and dog, along with several nights sleeping under the stars in the redwoods in Northern California.
I have tested the Magma 30 across three seasons in Southern Idaho, in early September and October in the Teton National Forest, in mid-June in Southern Montana, and late October in Humboldt County, CA. Low temperatures have ranged from 33°F to around 54°F and weather conditions I tested the bag in damp and misty weather, warm summer and chilly fall rain, and dry nights in the high desert. On warm nights, I unzipped the Magma 30 and used it as a quilt.
We also tested the REI Co-op Magma 30 sleeping bag alongside similar models in our Best Backpacking Sleeping Bags and Best Camping Sleeping Bags guides.
Performance in the field
Warmth and temperature accuracy
I found the Magma to be accurate in its listed temperature, if not a little warm. The Magma 30 has a tested range of 34°F and a tested lower limit of 24°F. The coldest night I’ve tested the Magma 30 the temperature was down to 33°F in the early morning, and I did not feel cold in the bag while wearing wool baselayer leggings and a long sleeve top along with a lighter weight midlayer and wool socks on.
I tend to find that I am a hot sleeper with the exception of my feet, which get cold and stay cold easily. I did not experience cold feet while sleeping in the Magma, and would unzip it on nights above 45°F when I felt too hot. If I needed to sleep in temperatures down to 30°F I would still use the Magma 30 but would not push it much further below freezing.
Comfort and sleep position
The Magma 30 is a bag made for those who want a traditional mummy-shaped bag but one that isn’t so tight it feels constricting. As a side sleeper, I am not a fan of mummy-shaped bags, but the 70 inches of shoulder girth and the 62.5 inches of hip girth in the Regular Wide size is enough for me to easily switch sleeping position.
The Magma 30’s wider shoulder and hip girth in the Regular Wide allowed for me to sleep on my side without the down fill being uncomfortably stretched across my hips.The insulated yoke, which hangs from the neck, can sometimes feel awkward when the bag is unzipped and when moving in your sleep, and it isn’t as cozy as a draft collar that’s sewn completely into the bag. That said, I haven’t felt much of a difference in temperature with the yoke vs. a draft collar in similar bags.
Warmth-to-Weight
I loved carrying the Magma 30 on the trail for its lightness—and for the comfort I could look forward to once I crawled into it at night. I tested the Regular Wide size, which weighs 1 lb 10 oz and is much lighter than the other bags I rotate through: the NEMO Disco Endless Promise (also a 30°F bag), which weighs 3 lbs 8 oz in the Regular Wide, or the Therm-a-Rest Boost 650 (a 20°F bag) which is 2 lbs 8 oz in the Regular Wide. (Read more about the Therm-a-Rest Boost 650 in our full review.)
REI Magma’s bag weight is so light because it uses a high-end 850-fill-power, water-resistant goose down that is bluesign approved, making for a lofty and warm bag that remains light. Unlike the Therm-a-Rest or the NEMO Disco, the lack of features such as vents, extra zippers, and arm holes also contribute to a lighter bag weight. The 15-denier shell fabric is also lighter weight than the shell fabric found on the Disco and shell fabric on the Boost..
Packability
REI includes a stuff sack and a mesh sack for storage. The provided stuff sack is fine for car camping or trips where I want it packed down but don’t need it to be as small as possible. For that, I’d use a compression sack (not included) to help me get it down in size.
On backpacking trips with my 60L backpacking bag (which is admittedly bigger than I usually need, but I tend to pack additional items for a dog) the Magma 30’s packed size has met my needs and expectations. I tend to start my trip with my bag in a compression sack but will ultimately stuff it loosely to fill space as I hike, and I tested the Magma using both methods in my Gregory Kalmia 60L and my items fit well both times.
In a smaller bag, like my Gregory Amber 44L, the Magma 30 took up too much space packed loosely, though I generally prefer to use a quilt when I use the Amber due to its smaller size.
Durability
The REI Co-Op Magma 30, along with its 15°F and quilt variants, are made with a thin shell of 15-denier recycled ripstop nylon. This thin shell hasn’t resulted in any rips in almost two years of heavy use. I've protected my bag byI primarily sleeping in a tent and storing my bag in the loose mesh storage bag in my temperature-controlled shop. In late 2024 I slept en plein air (outside of a tent, aka cowboy camping) a few nights in a row during a trip on the Redwood Creek Trail in Redwood National Park, and didn’t have any issues with durability.
On a recent car camping trip at City of Rocks National Preserve, we scooted our sleeping pads and bags out to the edge of a rough rock to sleep and stargaze, and the Magma didn’t get stuck on any of the spiky tree branches nearby or get scuffed against the rock. I would confidently say that the Magma is solidly durable.
Zipper
The Magma’s anti-snag zipper is effective and prevents annoying snags. too.
Water Resistance
The Magma 30’s water resistance was sufficient for my uses, especially when considering that it’s made with 850-fill-power water-resistant goose down, which can be slightly less hydrophobic than bags made with synthetic fill that is designed to wick and resist moisture.
Even while testing in the damp coastal rainforest of Humboldt and Redwood National Park, the bag withstood the damp fairly well. A few mornings of that trip, I woke up with a damp bag exterior, but I didn’t feel any moisture at all from the inside and it dried off after being hung in the sun for about an hour. On cloudy days and days where I couldn’t dry it off before moving, the bag was still dry to sleep in hours later, even if it was still cool to the touch and not bone dry on the outside.
Overall, I found it to sufficiently withstand the exceptionally damp environment of cowboy camping in the coastal rain forest but wouldn’t be comfortable using it over multiple nights where it got soaked or rained on.
Features
850-fill power water-resistant goose down (Bluesign approved)
The water-resistant, lofty, goose down felt true to its temperature rating. Since it is 850-fill down, it was not only warm but space down. The goose down is certified to the Responsible Down Standard and resists moisture.
Contoured hood
The Magma’s contoured hoodie shape secures snugly around the face and can be cinched up or down to customize warmth and coverage. The two differentiated drawcords are useful for easy adjustment when in the bag, but can be confusing to fight when you’re fully zipped in and may not be able to easily see or locate them.
Trapezoidal footbox
Many mummy bags can feel too constricting, even the footbox. The Magma’s footbox is trapezoidal, giving feet the room to move without excess space for warmth retention. Being able to stretch, move, and flex while fully enclosed in the bag is a useful feature.
Inclusive Sizing
The REI Magma 30 and 15 have the biggest size range of any other bags of similar fill power and weight. Sizes include Short, Short Narrow, Short Wide, Medium, Medium Wide, Long, Long Wide, creating options for a much wider variety of body sizes and heights than has been traditionally available in the outdoor industry. The design of the bag itself is created to contour to the body without being overly tight, creating a slightly roomier bag across all sizes.
Zipper and Zipper Paths
When zipped, the Magma 30’s zipper path wraps around to the front of the chest, a thoughtful design feature that makes it easier to open and close the bag from the inside. The zippers feature a drawstring pull that can be used from inside or outside of the bag and are designed to prevent snagging.
Interior Stash Pocket
The REI Magma 30 and 15 variants feature an interior stash pocket large enough for most cell phones or headlamps, though the flap that covers the opening can be difficult to maneuver at night or while you’re zipped in the bag.
Stuff sack and storage sack included
REI Co-op provides a 7.5 L stuff sack in the Regular Wide and a mesh storage bag for longer term storage and to retain loft. The stuff sack isn’t as packable as a compression sack and backpackers may want to purchase one or use one they already have if they want a smaller bag profile for packing and carrying.
Temperature variants
Magma 30°F
The 30°F variant is better for three season camping hovering above freezing temperatures. It’s a lighter bag at 1 lbs 10 oz in the Medium Wide and has less bulk than the 15°F variant. The bag is also less bulky than the colder temperature variant, with 4.7 L of compressed volume in the Medium Wide size.
Magma 15°F
The Magma 15 is made to handle colder, shoulder season temperatures and even into winter months that don’t dip into the single digits or lower teens. It’s a heavier model at 2 lbs 8 oz in the Medium Wide and has a compressed volume of 8.6 L, extra bulk and weight that is necessary to handle frosty nights.
Magma 30 Down Trail Quilt
The Magma 30 also comes in a Trail Quilt, REI’s offering for those who want to carry even less weight than the 30°F variant. It weighs 1 lb 6.3 oz in the Medium Wide, nearly 4 oz less than the mummy bag version. The quilt isn’t as size inclusive as the bags though, with only four size offerings: Medium, Medium Wide, Long, and Long Wide.
REI Co-op Magma 30 FAQ
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REI Co-op designed the Magma line to be gender neutral. Instead of assuming a set design based on binary understandings of body size and gender, REI created a bag built on extensive testing that is ultimately made to fit a variety of bodies/widths, rather than a specific gender.
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Yes, especially in the Medium Wide size I tested.
While a traditional mummy shape, the Magma 30 is made with side and active sleepers in mind, with a slightly wider cut across the chest and a trapezoidal footbox that feels roomy without excess bulk. Our tester is a side-sleeper who moves a ton during the night, and the bag moves with them with ease.
Similar sleeping bags
It’s difficult to compare the Magma 30 with other bags, largely because there are few other sleeping bags that compare with the Magma 30 in size range offered, that come in under 2 lbs of weight, and have a similarly high down fill power and price.
Therm-a-Rest Boost 650
Price: $340
Temperature rating: 20°F
Insulation: 650 fill down
Shape: Semi-rectangular
Weight: 2 lbs 13 oz
The Therm-a-Rest Boost 650 is a bag made for campers who occasionally backpack, don’t mind carrying more weight, and either don’t sleep cold or plan to only camp for three seasons. It’s also a bag made for those with luxury and cozy materials in mind. While the Magma 30 is soft to the touch, Therm-a-Rest’s 20-denier 100% recycled ripstop nylon is positively plush, feeling more like a blanket from home than a sleeping bag.
It’s also rich with features, like arm holes on both sides for venting and for easily using your hands while still warm and enclosed in the bag. The Therm-a-Rest Boost 650 lacks the same size range as the Magma, but the bag itself is still fairly inclusive, with the hip girth of the Medium Wide size at 74 inches, much larger than the Magma 30’s 62.5 inches of hip girth in the Regular wide. The extra space in the Boost 650 lends itself to cold pockets in the bag, and overall we didn’t find the Boost 650 to be consistently true to its temperature comfort rating, with the actual rating hovering about 5°-10° above what’s listed.
Ultimately, the Therm-a-Rest Boost 650 is for those who seek camp comfort but also want a high-quality bag that can be taken backpacking. Those who want a lighter bag that’s warmer should choose the Magma line of bags, even though they lack some of the fun features of the Therm-a-Rest Boost 650. Learn more in our in-depth review of the Therm-a-Rest Boost 650 sleeping bag.
Therm-a-Rest Boost 650
NEMO Disco 30 Endless Promise
Price: $280-300
Temperature rating: 30°F
Insulation: 650 fill down
Shape: Semi-rectangular
Weight: 1 lb 15 oz men’s, 2 lbs 4 oz women’s
The NEMO Disco 30 Endless Promise is another bag that, like the Therm-a-Rest Boost 650, offers lesser fill-power and more weight than the Magma 30, but has more accessories and features than the more straightforward Magma. The Classic Spoon silhouette is designed with side sleepers’ comfort in mind, and the bag comes in Regular, Regular Wide, and Long sizes. The Regular Wide NEMO Disco 30 is 2 lbs 6 oz and has 650 fill-power down. Both bags are rated for 30°F temperatures, but I find I sleep warmer in mid 30°F temperatures with the Magma 30 than I do the Disco Endless Promise.
The Disco Endless Promise has features that I wish I could have with the Magma, including Thermo Gill vents that can be zipped open or closed to increase ventilation as much as one needs.
The Magma has a similar compressed volume as the NEMO Disco Endless Promise; only 0.1 liter of a difference separates the Regular Wide Endless Promise (4.8L) with the Regular Wide Magma 30 (4.7L). The Magma tends to feel bulkier but both pack down easily, though the Disco Endless Promise feels slightly smaller when compressed into a pack. While both bags are similar, those looking for higher-quality down and less weight should choose the Magma 30.
Learn more in our in-depth review of the NEMO Disco Endless Promise Sleeping Bag.
NEMO Disco 30 Endless Promise
Men's
Women's
Should you buy the REI Co-op Magma 30 sleeping bag?
Buy if:
You want a custom feeling fit without the custom price, with 9 different size and height offerings.
You’re an active or side sleeper and need a few extra inches at the chest/shoulder area and footbox.
You’re looking for a straightforward, backpacking-friendly bag with high performance features at a more approachable price
Skip if:
You are looking for an abundance of built-in features and accessories.
You sleep cold, or just prefer to have a fuller coverage draft collar instead of the insulated yoke.
You prioritize absolutely minimal packability and compression. The Magma is pretty minimal but you're likely best served by a backpacking quilt.
Where to buy the REI Co-op Magma 30 sleeping bag
The REI Co-op Magma 30 sleeping bag is available at REI stores and online.
REI
Pros: 100% satisfaction policy for 1 year; 10% dividend for members.
Why you should trust us / About the author
I am a former outdoor educator and camp professional who knows that choosing the right gear for your outdoor adventures can make or break your experience. For many years I did not have access to a lighter bag for backpacking that was also size inclusive, and I spent many miserable hikes and trips carrying a heavy and bulky bag.
I know the value of finding gear that is made to truly fit a wider variety of bodies, and have been writing and testing gear and outdoor clothing in plus and extended sizes for 5 years with Treeline Review. I have tested bags and gear in rain, snow, and humid and dry conditions, carried them ten steps from car to campsite and over miles in the Sawtooth National Forest or Caribou-Targhee National Forest, where I spend most of my time camping, hiking, backpacking, and paddling. Finding gear that fits and keeps you going is essential, and I am lucky to share my learnings and experiences through guides with Treeline Review.
Read more of Gabi Reyes-Acosta’s gear reviews at her author bio at Treeline Review.
