ultralight sleeping bag reviews

A backpacker above the Cutthroat Lakes on the Doubletop Mountain Trail in Wyoming's Wind River Range.

The Best Backpacking Gear of 2025

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By Michael Lanza

Utah’s High Uintas Wilderness, Montana’s Beartooths, and Colorado’s Weminuche. Glacier National Park and the Tetons. The Grand Canyon (repeatedly). The Canadian Rockies. Southern Utah’s Owl and Fish canyons. The Wind River Range. The John Muir Trail and Wonderland Trail. Iceland’s Laugavegur and Fimmvörðuháls trails. New Zealand’s Milford Track, Routeburn Track, and Tongariro Alpine Crossing. These are just some of the places where I’ve recently tested the backpacking gear and apparel that I’ve reviewed at The Big Outside—so that I can give you honest and thorough, field-tested opinions that help you find the best gear for your adventures.

And that’s exactly how I came up with the following picks for today’s best backpacking gear.

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Sea to Summit Spark Pro -9C/15F ultralight sleeping bag.

Review: Sea to Summit Spark Pro -9C/15F Sleeping Bag

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Ultralight Sleeping Bag
Sea to Summit Spark Pro -9C/15F Bag
$649, 1 lb. 11 oz./765.4g (regular)
Sizes: unisex regular and long ($689)
seatosummit.com

We woke up from our first night in Colorado’s San Juan Mountains in mid-September, at well over 10,000 feet beside a creek that sang soft lullabys to us all night, to find ice crystals in our water bottles and one full water bladder that had been left outside the tent partly frozen. But the overnight temperature dropping to below freezing had hardly registered with me as I slumbered soundly zipped up inside my Sea to Summit Spark Pro -9C/15F sleeping bag—one of the warmest for its weight, most packable, and well constructed ultralight sleeping bags you’ll find.

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The Marmot Hydrogen 30 ultralight sleeping bag.

Review: Marmot Hydrogen 30 Sleeping Bag

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Ultralight Sleeping Bag
Marmot Hydrogen 30
$399, 1 lb. 9.4 oz./720g (regular)
Sizes: unisex regular and long ($419)
backcountry.com

For backpackers prioritizing low gear weight who don’t tend to get cold very easily, a sleeping bag rated 30 degrees Fahrenheit can function as their go-to for most three-season trips. And Marmot’s Hydrogen 30 remains one of the perhaps three highest-quality and warmest ultralight mummy bags at this temperature rating, as I affirmed sleeping in it for two nights on southern Utah’s Owl and Fish canyons loop in early May, four nights in Montana’s Beartooth Mountains in August, and five nights on the Grand Canyon’s Gems Route in mid-April.

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The Mountain Hardwear Phantom 30 sleeping bag.

Review: Mountain Hardwear Phantom 30 Sleeping Bag

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Ultralight Sleeping Bag
Mountain Hardwear Phantom 30
$480, 1 lb. 6 oz./624g (unisex regular, 72-inch)
Sizes: unisex short ($440), regular, long ($480)
backcountry.com

Look at specs when shopping for a high-quality, ultralight, three-season sleeping bag and you might quickly trim your short list to about five models, all at basically similar weights and price points. But having slept in most of those top bags—and after sleeping in Mountain Hardwear’s Phantom 30 on cool nights on backpacking trips from a section of the Arizona Trail in the first days of April and camping at Idaho’s City of Rocks in June to the Canadian Rockies and Wind River Range in August—I place the Phantom 30 among the two or (maybe) three very best ultralight mummy bags for its strategic balance between low weight and excellent warmth. Here’s why.

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The Therm-a-Rest Vesper 32 Quilt ultralight backpacking quilt.

Review: Therm-a-Rest Vesper 32 Ultralight Backpacking Quilt

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Ultralight Backpacking Quilt
Therm-a-Rest Vesper 32 Quilt
$380, 16 oz. (regular)
Sizes: regular and long
backcountry.com

For seven nights in huts on Iceland’s Laugavegur and Fimmvörðuháls trails in July—and to fit all of my clothing layers, food for a week, and other stuff inside my 40-liter pack while keeping it as light as possible—I decided to take the Therm-a-Rest Vesper 32 Quilt for its minimalist weight and excellent packability. And it turned out, that hut trek mimicked sleeping outside on mild nights, presenting ideal circumstances for weighing an ultralight backpacking quilt’s strengths and shortcomings.

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