Bikepackers are a demanding bunch, we want our kit to be small and lightweight, but still offer excellent performance. Sometimes that can mean taking a sacrifice in comfort, whether that's out on the trail when you wish you had packed an extra layer, or at home while you save up to buy premium kit in order to save every possible gram.
Sea To Summit knows a thing or two about sleeping outdoors and its sleep systems are already a popular choice for bikepacking. The Australian outdoor brand sells a wide range of camping mats but the Ultralight model has been a solid performer in the range since 2015. We have been camping out under the stars to see how it performs.
Design and specifications
Sea to Summit claims the mat on its own weighs 395g although our medium sample actually tipped the scales at 365g which is a pleasant surprise. That means the Ultralight is certainly low weight, however, it's not the lightest on the market and it's not even the lightest in the Sea to Summit's range, the Ether Light XT Sleeping Mat takes that title. Importantly though it manages to achieve this low weight without resorting to very delicate 20D fabrics or larger pack sizes.
The Ultralight uses 30D and 40D TPU laminated fabrics. On the outside it's Sea to Summits trademark yellow, but on the inside it's white which is treated with an antimicrobial treatment to try to stop unpleasant things from growing inside your mat.
The mat comes in three sizes (Small, Medium, and Large) which allows you to optimize your mat size based on your height. Our medium mat measures 183cm by 55cm and all the sizes have a depth of 5cm.
While there are many different camp mat designs, the most common designs are either long baffles or a sprung cell pattern used here, The Ultralight features 331 independent Air Sprung Cells across the matt which helps support the body off the ground and is said individually move to distribute pressure.
Sea to Summit includes a repair kit with some patches and for maximum luxury, you can buy Sea to Summit pillows that attach to the mat so they don't escape at night.
Saving a few grams on your camping mat may not be the most efficient area to lose weight on your overall bikepacking setup, but the Ultralight’s small pack size is certainly a boon when it comes to packing up. Despite having considerably more inflated volume than my usual Klymt Ozone mat, it packs just as small.
Other than the compact size, the biggest win for me with the Ultralight mat is the Airstream Pumpsack inflation process. Rather than hurriedly wheezing bits of dinner into your mat as you try to quickly set up camp before the sun goes down, Sea to Summit has integrated an inflator into the stuff sack, which should stop the build-up of nasty stuff inside your mat but also speeds up inflation. The sack pops into the valve and then it's just a case of trapping some air inside the stuff sack before giving it a squeeze to push the air through the valve. It only takes around four sacks of air before the mat is inflated and the one-way valve means you don’t lose any air between squeezes.
I switch between being a side sleeper and a back sleeper and the 5cm depth was just enough to stop me from touching the ground during the night even though I was sleeping on some pretty uneven surfaces. It's still air-tight despite only using my bivy bag to protect it from the ground and I will continue to use the mat and update this review if it does develop a leak.
The valve can be completely opened to let air freely escape which makes folding and rolling a much easier job and speeds up getting back on the bike and rolling come the morning. You can also open the one-way valve and let a little air out by pressing it with your finger.
It must be noted that the small size and pack weight is great but come at the cost of warmth. The Ultralight is only rated to a 1.1 R-Value as it has zero insulation so it's probably not recommended for cold temperatures. If camping in the cold is your thing then Sea to Summit does an insulated version too which adds 80g and should be a good bit warmer. During my summer camp testing, I had no problems with temperature with the standard one and would probably be happy taking it out during shoulder seasons too – it must be noted I do run quite warm when I sleep.
The Sea to Summit Ultralight strikes a good balance between cost, comfort, weight, and pack size. I found it to give a good night's sleep whether I was on my back or side and it smoothed out lumpy ground well. The Airstream Pumpsack is a stand-out feature and makes inflation fast, easy, and should help extend the life of your mat too.
Tech specs: Sea to Summit Ultralight mat
- Price: $139 / £95
- Materials: 30D/40D
- ASTM R-Value: 1.1
- Dimensions: 169x55cm (Small), 183x55cm (Medium, tested), 198x64cm (large)
- Depth: 5cm
- Pack size: 7.5x17cm (small, medium), 7.5x20cm (large)
- Weight: 367g (matt only), 417g including stuff sack and repair patches (medium)