Sea To Summit Ultralight Insulated Air Sleeping Pad Review
An in-depth review of Sea to Summit’s Ultralight Insulated Air, a comfortable sleeping pad for side sleepers
June 19th, 2025
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Our verdict
The Sea to Summit Ultralight Insulated Air has a pocketed (rather than baffled) design, which helps side sleepers feel more comfortable while backpacking. Side sleepers often find that inflatable sleeping pads don’t offer enough padding for a comfortable night of sleep in the backcountry. With the Sea to Summit Ultralight Air, those pockets distribute the weight as you move and make it less likely side sleepers will bottom out compared to sleeping pads with vertical or horizontal baffles.
Similarly priced to other inflatable pads, the Sea to Summit Ultralight Insulated Air has an R-value of 3.1 (the women's version has an R-value of 3.5 and weighs an ounce less). The Ultralight Insulated Air comes with an innovative stuff sack / Airstream Pump combination which allows you to inflate the pad with one breath.
While other brands are replicating this stuff sack pump, Sea to Summit’s system still is the most efficient and reliable.
We've tested the Sea to Summit Ultralight Insulated Air sleeping pad on thousands of miles of backpacking trips from the Arizona Trail to the Blue Mountains Trail and Oregon Desert Trail. It's so good we keep reaching for it trip-after-trip.
You can find more of our favorite sleeping pads in our Best Backpacking Sleeping Pads guide.
Sea To Summit Ultralight Insulated Air Sleeping Pad
Unisex
Women's
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Specs
R-Value (unisex): 3.1
R-Value (women’s): 3.5
Seasons: 2.5 to 3
Thickness: 2”
Shape: mummy
Weight: 12.3 to 21.0 oz (excluding pump sack)
Inflation: Airstream Pumpsack
Lengths: 50”, 66”, 72”, 78”
Fabric: 30D / 40 D nylon
Insulation: Thermolite
Repair kit: included
Pillowlock system: included
Comparison Table
| SLEEPING PAD | WEIGHT (ounces) | TYPE | PUMP SACK? | R-VALUE | THICKNESS (inches) | PACKED SIZE (inches) | LENGTHS (inches) | WARRANTY |
|---|---|---|---|---|---|---|---|---|
| Sea To Summit Ultralight Insulated Air Sleeping Pad (Unisex) | 12.3 to 21 oz | Inflatable | Y | 3.1 | 2.0 | 9 x 4 | 50, 66, 72, 78 | Lifetime guarantee |
| Sea to Summit Ultralight Air Insulated (Women's) | 17 to 21 oz | Inflatable | Y | 3.5 | 2.0 | 9 x 3.75 | 66, 72 | Lifetime guarantee |
| Sea to Summit Ultralight Insulated Air Sleeping Mat | 12.3 to 15.1 oz | Inflatable | Y | 3.1 | 2.0 | 4 x 9 | 50, 66 | Lifetime guarantee |
| Sea to Summit Ultralight Air | 12.2 to 17.4 oz | Inflatable | Y | 1.1 | 2.0 | 3.5 x 7 | 62, 76, 78 | Lifetime guarantee |
| NEMO Tensor All Season Insulated Sleeping Pad | 14.1 to 20 oz | Inflatable | Y | 5.4 | 3.5 | 4 x 10 | 72, 76 | Lifetime |
What we liked
Comfortable for side sleepers
One breath to inflate
Easy-to-use pump sack system
Single multi-function valve is easy to use and effective
Compact and packable
Pillow lock system keeps your pillow in place all night long
Relatively quiet fabric makes for a better night’s sleep
What could be better
Heavier than some backpacking pads on the market
2" thickness may not be thick enough for some people
Bottoms out when sitting on it
Features
Air sprung cell design
As side sleepers who find the NeoAir XLite to be too uncomfortable for quality sleep in the backcountry, we have found the Air Sprung Cell design on the Sea to Summit revelatory.
Sea to Summit says this design is similar to springs on a sprung mattress. Each cell is an interconnected chamber. Sea to Summit makes this Air Sprung technology in multiple sizes, and the Ultralight Insulated Air uses medium resolution cells for the lightest and smallest pack volume to appeal to backpackers.
The pad itself is 2" thick, which is fairly close to the ground for inflatable sleeping pads these days. Still, the design provides comfort far superior than other sleeping pads of similar height.
Single valve inflation and deflation
The Sea to Summit Ultralight Insulated Air pad has one of the best inflation systems in the industry. As advertised, it only requires one breath to inflate. It uses a single valve for inflation and deflation. It's easy to use and extremely effective at efficiently inflating a sleeping pad.
What I really love, however, is the “fine tune” button within the valve. I like to find that goldilocks inflation level — not too much, not too little, but just right. So I inflate the pad to the max, then let some of the air out via the fine tune button. It’s perfect.
Insulation
The Sea to Summit Ultralight Insulated Air is made with Thermolite HL-1 insulation giving it an R-value of 3.1. The women's version has an R-value of 3.5. R-value is a measure of insulation and anything around 3 is pretty solid for 3-season backpacking.
R-value measures how well your pad will prevent convective heat loss moving from your warm body to the cold ground. You can read more about what R-value means in our Best Backpacking Sleeping Pads guide.
The Thermolite HL-1 in the Ultralight Insulated Air is a high-loft insulation that is fiberfill constructed. Most synthetic insulation is either hollow-core or solid-core fibers and is placed in specific patterns. Sea to Summit says the Thermolite mixes hollow-core and solid fibers for better durability and lighter-weight warmth. The Thermolite is placed inside the Air Sprung Cells so they each provide insulation. You can read more about synthetic insulation in our Best Synthetic Jackets guide.
Length options
One of our favorite things about the Sea to Summit Ultralight Insulated Air are the variety of length options. This is the only sleeping pad we've seen offered in x-small, small, regular, and large. The XS is 50" long and is especially great for kids, shorter people, and people who want a ¾ length pad. The large goes up to 78".
Weight
While this pad works really well for side sleepers, our main beef remains the weight. It runs at 16.9 ounces, not including the stuff sack / Airstream Pump. This seems like overkill when pads like the Therm-a-Rest NeoAir XLite NXT are only 13 ounces, or more insulated pads like the Therm-a-Rest NeoAir XTherm NXT are only 16 ounces for 1.5 times the R-value.
Still, if you’re a side sleeper who is willing to pay in both dollars and weight to finally have a comfortable night’s sleep in the backcountry, you might want to take a look at the Sea To Summit Ultralight Insulated Air.
Fabric
The Sea to Summit Ultralight Insulated Air uses 30D and 40D nylon, which is on the thicker side for an ultralight pad, meaning it is more durable. They add an anti-microbial TPU lamination to prevent the buildup over time of bacteria from moisture in your breath or the air. The TPU lamination also helps reduce delamination, which can be a problem with some other brands of sleeping pads.
I love that the fabric doesn't feel as slick as other ultralight pads, such as the Therm-a-rest NeoAir XLite. I usually don't sleep in long underwear, so the tactile feeling of the pad material is important to me.
I also love that the fabric is relatively quiet. Those of you who’ve used an OG Therm-a-Rest NeoAir know what I’m talking about.
Pillow Lock System
All Ultralight Insulated Air pads come with Sea to Summit’s pillow lock system. It’s essentially some hook and loop self-adhesive strips that connect the pad to the Sea to Summit Aeros Ultralight Inflatable pillow. The good news is that, unlike Velcro, the strips won’t snag other fabrics! Read more about our favorite backpacking pillows.
Anti-microbial interior
An anti-microbial treatment is applied to the interior TPU lamination to inhibit mold growth. I appreciate this for long-term use.
Value
The Ultralight Insulated Air is reasonably priced for a top-of-the-line, well-constructed backpacking sleeping pad. While other brands are charging upwards of $250 for a sleeping pad, the Sea to Summit is a reasonable $180 for a regular size pad. You can even get this pad in a x-small size for $160. Considering our model has lasted us multiple thru-hikes, we consider that a fair price.
Performance in the Field
Comfort and warmth
As stated in our Arizona Trail Gear List, we found a lot to like with the Sea to Summit Ultralight Insulated. With an R-value of 3.1, it was definitely warm enough even on below-freezing nights (yes, Arizona gets below freezing, especially at 9,000 feet).
Thanks to the cellular design I never rolled off my pad.
Unfortunately, although this pad is better for side sleepers than the XLite or other horizontal baffled pads, as a side sleeper, our hips still bottomed out which caused some pain during the night.
Inflation
At the end of a long day of hiking at altitude, only requiring one breath to inflate the Ultralight Insulated Air was a game-changer. The Sea to Summit air pump is one of the best in the industry. It's easy to use and extremely effective at efficiently inflating a sleeping pad.
Noise
The fabric is quiet and didn’t bother us while turning over during the night. We can't say the same for other sleeping pads.
Durability
We initially had some durability issues. It popped after only 7 nights on the trail (admittedly, we were hiking through cacti-filled Arizona, but...). We were able to patch it and it was fine for the rest of the trip and has lived on for thousands of miles of trips on other long-distance trails, including the Blue Mountains Trail and Oregon Desert Trail.
Other versions
We recommend staying clear of the similarly-named, similar-looking Sea to Summit Ultralight Air Pad, at least if you're a cold sleeper. This pad has the pocketed advantages of the Ultralight Insulated but (you guessed it) doesn’t have much of an R-value (only 1.1), making it a 1.5-season pad at best.
Sure, it won a National Geographic Gear of the Year award. But it has an R-value of 1 (less than a foam pad), which isn’t enough for spring or fall travel and won’t be enough for most people backpacking at altitude in the mountains in summer.
Should I buy the Sea to Summit Insulated Air Pad
You should buy if:
You're a side sleeper
You're willing to sacrifice a little extra pack weight for more sleeping comfort
You don't like the super-slick material of the Therm-a-Rest NeoAir XLite
You should buy the women's version if:
You want a higher R-value and lower weight (seems like funky math, but the weight savings comes via narrower width and shorter length)
You should skip if:
You want the lightest possible sleep system
You sleep well in the backcountry no matter what pad you're using
You're looking for a 4-season pad
Where to buy
REI
Pros: 12-month warranty, 10% dividend for members
Amazon
Pros: free 2-day shipping for Prime members
Sea to Summit
Pros: all sizes and lengths are available
About the Author / Why you should trust us
Naomi Hudetz is co-founder and director of analytics and digital innovation and leads business strategy and revenue operations for Treeline Review. She brings decades of private sector experience in project management, budget and pricing projection, and long-term business vision, strategy, and goals.
Naomi left her corporate career to pursue her passion for the outdoors. She received the Triple Crown award for hiking for completing the Appalachian Trail, Pacific Crest, and Continental Divide Trails and has hiked numerous other distance routes including the Great Divide Trail across the Canadian Rockies (twice), Grand Enchantment Trail, Pacific Northwest Trail, the Arizona Trail, (most of) the Idaho Centennial Trail, the first known thru-hike of the Blue Mountains Trail, and the Oregon Desert Trail. She recently bikepacked the Great Divide Mountain Bike Route.
She previously served as Treasurer of the American Long Distance Hiking Association-West, and is currently on the board of the Continental Divide Trail Coalition. She’s based in White Salmon, Washington.
