Sea To Summit Sleeping Bag and Mat Review

Erin McGrady and Caroline Whatley are laying on two teal blue sleeping mats. On top of those mats are sleeping bags. The one on the left is lime green and the one on the right is bright blue. Erin is on the left, Caroline is on the right. They're inside of a camper van and on top of wooden boxes. The doors are open and they're laying down facing one another.

In this post we’re going to share our thoughts on the latest Sea To Summit Sleeping Bags and Mats. Specically, we’re taking a look at Sea To Summit’s Altitude AtII Sleeping Bag, Ascent AcII Sleeping Bag, and the Comfort Light S.I. Self Inflating Mat. Up until now we’ve been using Kelty’s Double Wide Sleeping Bag and two homemade DIY foam pads for our camper van bed. And while we’ve slept pretty good with that system, we jumped at the chance to test out other gear. Keep reading to learn about our Sea To Summit Sleeping Bag and Mat Review.

a photo of the inside of a van. there are two wooden boxes in the van and on top of them rest two teal sleeping mats. On top of the mats is, on the left, a Sea To Summit black bag containing a sleeping bag. To the right of that is a teal blue sleeping bag that is ready to be laid in.
Our camper van bed setup took 3 minutes to get the mats out and opened up and the sleeping bags pulled out of their storage bags.

Sea To Summit Altitude AtII Sleeping Bag

For starters, the Sea To Summit Altitude AtII Sleeping Bag comes in its own stuff sack and larger mesh bag. The stuff sack has a handle and a label on the outside. The mesh bag is fairly loose and easy to get the sleeping bag into. Both are great for transporting the sleeping bag though we wouldn’t recommend storing the bag in either for prolonged periods of time because like all down products, it’ll negatively impact the loft and therefore ability to keep you warm.

Sizing and Weight

The Altitude AtII bag itself is a bag specifically designed for women. It comes in two sizes, Women’s Regular and Women’s Long. We tested the Women’s Long. The Regular sized bag is suitable for people 5’7″ or 170cm or under. The Women’s Long is suitable for people who are 6″ or 183cm or under. The Long bag also has a few more inches in width. This bag weighs in at 3 pounds, 1 ounce which means it’d be great for backpacking, car camping, or even just for delivering extra warmth as you watch the sun set on the Blue Ridge Parkway. Note: If you don’t need the extra length you can cut down on weight as the Regular bag weighs 2 pounds, 13.2 ounces.

Temperature Rating

Now when it comes to sleeping bags one of the first things we take note of is the temperature rating. This one is rated down to 15°F meaning you’ll be comfortable in temps down to 15°F. I have never camped in 15°F and unless someone invites us on a winter expedition, I may never put myself in that scenario. Still, if I was, this bag would do the job as it’s lower limit is 2°F and it’s extreme limit (survival) is -37°F. As far as our purposes go, it worked great in the mid 40°F degree temperatures that we tested it in. For our three-season camper van travel pursuits, this bag will more than do the job. To be clear, though this bag is rated with some pretty extreme temperature ranges, we do not and Sea To Summit does not recommend using these bags in such extreme temperatures such as those well below freezing.

Materials and Construction

Sea To Summit Makes synthetic sleeping bags and ULTRA-DRY Down Sleeping Bags. Both of the ones we tested fall into the latter category. The ULTRA-DRY Down is not only RDS certified but it also undergoes a water-repellent treatment which helps protect the down from the elements and also condensation which is a legit challenge in a camper van. This treatment helps keep the down from taking on water, weight, and a bad smell. THERMOLITE panels can be found at your feet for additional warmth on this bag which helps keep your toes warm. One of my favorite things about this bag though is the feel of the 20D Nylon shell. It’s soft to the touch and when you’re inside, it feels super cozy and warm.

Sea To Summit Ascent AcII Sleeping Bag

Just like the Altitude AtII mentioned above, Sea To Summit has also given the Ascent AcII Sleeping bag a stuff sack and mesh bag. Similar storage guidelines apply. Side by side the Ascent AcII is smaller in size compared to the Altitude AtII.

Sizing and Weight

This bag doesn’t have a gender specification. There are, however, two options when it comes to this bag: Regular and Long. The Regular bag has a max user height of 6″ or 183cm or under while the Long bag can accommodate people who are 6’6″ or 198cm tall. We tested the Regular bag. The Ascent AcII weighs 2 pounds 10.2 ounces. It’d be perfect for both backpacking trips and camper van adventures.

Temperature Rating

The temperature rating for the Ascent AcII Sleeping Bag is similar to the Altitude AtII. Sea To Summit says you’ll be comfortable in this bag at 27°F. It has a lower limit of 15°F and an extreme rating at -19°F. What this means is that your average woman would be comfortable in this bag in air temps as low as 27°F. Your average man, however, would be comfortable in air temps as low as 15°F. This bag was perfect for our overnight camping trip in the mid-forties.

Materials and Construction

Just like the Altitude AtII, the Ascent AcII is also made with RDS Certified down that’s undergone ULTRA-DRY Down treatment. This means you’ll stay warm and also have protection against moisture. Though the Ascent AcII doesn’t have THERMOLITE panels at your feet, it is constructed with the 20D Nylon like the Altitude AtII and is just as soft against your skin.

Sea To Summit Comfort Light S.I. Sleeping Mat

a photo of a white camper van with the two back doors open wide. The sun is shining on the van. There are two wooden boxes in the photo that two teal sleeping pads rest on, side by side. Next to the wooden boxes, on the left, is a blue plastic water jug.
Unlike some of the other camper van beds we’ve tried, these pads are slim, inflatable, and easy to work with.

A sleeping bag is only part of the equation when it comes to sleeping comfortably in the outdoors. The idea goes that while you want to keep your body warm with a sleeping bag, you’ve also got to have a layer of insulation between you and the ground. Or, in our case, our bodies and the boards on the van bed. A mat or pad serves the dual purpose of keeping you warm but also offering a little extra padding.

Sea To Summit’s Comfort Light S.I Mat (Regular size) clocks in at 1 pound 5 ounces which makes it great for car camping and backpacking. The Large weights 1 pound, 9 ounces. It’s not the lightest on the market BUT it is super durable. The extra weight is well worth it and it’s due to the air proof barrier (laminate) behind it that makes this mat so durable and reliable. For us, camping in the van doesn’t mean we’re likely to puncture it on rocks or dirt, but there are some corners on the wooden boxes in our van that have snagged more than a few things. We don’t have to worry about that with this mat. Plus, if we do want to have a layer between us and then ground when eating or relaxing outdoors, we can do so on this mat.

Another great feature about this mat is that it’s self-inflating. This means you don’t have to carry a pump or make yourself dizzy blowing it up. When filled with air, the R-value is 3.7. The pad is shaped like a mummy which helps reduce weight and bulk but if you’re the kind of person who will be doing mostly car camping you might want some additional surface area and padding. But for the person who will do a combination of backpacking and car camping this is a great option.

The Comfort Light S.I. Mat has grippy silicon design on the bottom so that the mat stays in place. This is a great feature to have because it eliminates the annoying ‘walking’ mat that requires constant adjustments.

Two hands hold a teal blue sleeping pad. the hand on the left cradles the pad while the hand on the right holds open the valve.
The Sea To Summit Mat is self-inflating. It’s also easy to get the air out of the mat when it’s time to pack up.

The first time you use this self-inflating mat, you’ll need a few hours for it to expand and inflate. After that, it won’t take hours. It’ll be ready for use by the time you finish setting up the rest of your camp. And if not, the inflation valve is easy to blow into if you want to speed up the inflation process. When it’s time to head home, the air releases out of the mat fairly easily. Unlike other sleeping pads, this one didn’t fight too hard with us to go back into the bag.

Bonus: each mat comes with it’s own patch kit in case you snag it on a rock and create a small puncture. Also, the mats are available in a regular and long length. We have one of each to pair with the regular and long length sleeping bags.

Recap of the Sea To Summit Sleeping Bag and Mat Review

Aesthetically speaking, we really love the way the Sea To Summit Sleeping Bags and Mats look. They come in bright, vibrant colors that not only look stylish and modern but that helped make our photographs pop.

Though we love that these mummy-style sleeping bags keep us warm, our favorite feature was that the zippers coupled up meaning we could pair them up with one another and create a double-wide bag that we could both fit in. Yay cuddling!

Our second favorite feature, also found on both bags, is the large internal pocket. You can access it without having to unzip the bag. It’s great for storing your phone and for us, keeping our camera batteries warm.

Ready to buy? Want to learn more? Click on each link below on Sea To Summit’s website:

Seat To Summit Altitude AtII Sleeping Bag
Sea To Summit Ascent Ascent AcII Sleeping Bag
Sea To Summit Comfort Light S.I. Sleeping Mat

Published by Erin McGrady

Erin McGrady is a filmmaker, photographer, and writer exploring Asheville and beyond. My work focuses on sharing about LGBTQ safe spaces, camper van life, and the outdoors.

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