Sea to Summit Sleeping Bag Liners: Every Adventure Will Be Covered

Whether you’re a dedicated camper who spends most of your weekends in a tent, or a backpacker who hasn’t set foot on home soil in six months, we can probably all agree that there’s certain things we miss about home. One of those things is the comfort of fresh, clean bed linen. A great way to recreate this wonderful feeling away from home is to use Sea to Summit sleeping bag liners.

No matter how far away from home you are, you can be sure of a great night’s sleep in clean and familiar bedding.

But you can’t go out and buy just any liner. This article is designed to provide you with the features you should look for, and the great benefits you can experience by taking one with you on your camping trip.

Best Sea to Summit Sleeping Bag Liners on the Market

Note: We get commissions for purchases made through links in this article

Sea to Summit Reactor Extreme Thermolite Liner

Sea to Summit Reactor Extreme Thermolite Liner

Weight: 14 ounces 

Dimensions: 210cm x 90cm

Specific features: Thermolite fabric. Mummy shape with a box foot. Draw cord hood with mini cord lock

Best use: Winter campers looking to add extra warmth to their sleeping bag

Description: This Reactor Extreme Thermolite liner is a great addition to your winter camping kit. The bag has 110g/m2 of Thermolite lining, ensuring that you stay toasty and warm whatever the weather outside. In fact this bag adds a massive 25F (14C) of warmth to your sleeping bag.

This liner also packs into its own Ultra-Sil stuff sack meaning it’s always easy to find, especially at the end of a trip when you want to throw it in the wash. Whilst this liner is a classic mummy space, the cut of the fabric is spacious enough that you won’t feel constrained.

The hood means that you can cover your head to stay warm even when it’s blowing a blizzard outside. Users have commented on the quality of the soft and lightweight fabric of this liner, however some have noted that whilst it adds a fantastic amount of warmth, it may not be quite the 25F advertised.

Check the price on Amazon

Sea to Summit Reactor Thermolite Sleeping Bag Liner

Sea To Summit Reactor Thermolite Sleeping Bag Liner

Weight: 9 ounces 

Dimensions: 210cm x 90cm

Specific features: Mummy shape with a box foot. Draw cord hood with mini cord lock

Best use: Campers, backpackers or travelers looking for a warm and cozy addition to their pack

Description: This soft Thermolite Sleeping Bag liner adds up to 15F of warmth to your sleeping bag but its low weight and small size means you won’t feel weighed down on your way to your destination.

Machine washable for ease of use, many users also take this on backpacking trips to save renting sheets in hostels, or for use on planes. Also great for summer camping when the nights are too hot for a regular sleeping bag. Packs into its own stuff sack so it’s easy to pack away and to find in your bag. Some users note that this will not keep you warm enough on winter trips so that’s something to think about if you plan on camping in very cold conditions.

Check the price on Amazon

Sea to Summit Reactor Plus Compact Thermolite Mummy Liner

Sea to Summit Reactor Plus Compact Thermolite Mummy Liner2

Weight: 9.3 ounces 

Dimensions: 183 cm x 90 cm

Specific features: The first dual fabric sleeping bag liner. Compact design for users under 6 feet tall

Best use: Campers looking for maximum warmth with minimum weight

Description: This Reactor Plus Compact Thermolite black and orange liner brings a new development to the market: dual fabric with extra warmth where you need it most. Sea to Summit’s standard 80g/m2 fabric is combined with panels of 110g/m2 in the core body and foot bed areas.

This means you get warmth where required, without compromising on weight. The fabric is soft against your skin, unlike the standard cold polyester lining of most sleeping bags. This liner adds an extra 20F of warmth to your sleeping bag. Some users have complained about the fact that quite a bit of static electricity is generated by this fabric, so that’s something to bear in mind. This liner won’t suit taller or larger users due to its compact size.

Check the price on Amazon

Sea to Summit Adaptor CoolMax Sleeping Bag Liner

Sea to Summit Adaptor CoolMax Sleeping Bag Liner

Weight: 9 ounces 

Dimensions: 210cm x 90cm

Specific features: Climate control fabric adapts to a variety of temperatures and humidity

Best use: Ideal if you’re travelling to warm, humid conditions

Description: Designed with warm or humid conditions in mind, the CoolMax fabric of this liner is specifically designed to keep you cool and dry while you sleep.

The Adaptor CoolMax Sleeping Bag liner works to wick excess moisture away from your body, for a comfortable night’s sleep. This liner is perfect to use on its own, or on cooler nights, you have the option of layering up with a lightweight sleeping bag. The CoolMax fabric is comfortable, soft and stretchy so you won’t feel constrained by this liner.

Check the price on Amazon

Sea to Summit Coolmax Adaptor Liner with Insect Shield

Sea to Summit Coolmax Adaptor Liner with Insect Shield

Weight: 9 ounces 

Dimensions: 210cm x 90cm

Specific features: Insect shield technology

Best use: Travelers in hot and humid regions who also want to avoid being bitten by insects

Description: Featuring all the benefits of Sea to Summit’s standard Coolmax Adaptor liner, with the added advantage of insect repelling qualities. The fabric of the liner has been treated with Permethrin, providing invisible and odorless protection against insects.

The Coolmax Adaptor Liner with Insect Shield fabric will also keep you comfortable due to its moisture management abilities. Any moisture is wicked away from your body to evaporate on the outside of the liner. This liner packs up really small, about the size of a softball. Users commented on how effective the insect shield technology is at repelling those bugs, but some did note that the effects do wear off after repeated washings.

Check the price on Amazon

Sea to Summit Thermolite Reactor Fleece Liner

Sea to Summit Thermolite Reactor Fleece Liner

Weight: 15 ounces 

Dimensions: 200cm x 70cm

Specific features: Soft brushed fleece and extreme warmth rating, quarter zip for ease of access. Mummy shape with paneled hood.

Best use: Extreme winter conditions

Description: The quarter zip and soft fleece fabric are what sets this liner apart. The zip makes this sleeping bag liner much easier to get in and out of than the majority of liners, which are a little more restrictive.

This Thermolite Reactor Fleece Liner has Sea to Summit’s Thermolite technology but with a soft fleece finish, making this one of the warmest liners out there, adding a full season warmth to your sleeping bag. It can also be used as a summer sleeping bag, on its own. This liner is slightly smaller than some, which is great if you’re looking for a snug fit to keep you warm, but if you’re taller or larger than average then you may find this a little on the small side.

Check the price on Amazon

Sea to Summit Coolmax Adaptor Traveler Liner

Sea to Summit Coolmax Adaptor Traveller Liner

Weight: 12 ounces 

Dimensions: 225cm x 92cm

Specific features: Classic traveler shaped liner, with pillow insert

Best use: Backpackers and campers looking for a traditional shaped liner in a high-tech fabric

Description: This CoolMax Adaptor Traveler liner provides a comfortable stretchy fabric which can be used on its own or with a sleeping bag. The traveler shape has a pillow insert making this ideal for use in hostels instead of renting sheets.

The bag features a contrasting color along the top edge in order to make it easier to locate the top of the bag. The Coolmax fabric wicks moisture away for a comfortable night’s sleep in a soft fabric. Users have reported that this liner dries quickly and washes well, and that the fabric is stretchy and comfortable, so you won’t feel restricted in this liner.

Check the price on Amazon

Sea to Summit Expander Travel Liner

Sea To Summit Expander Travel Liner

Weight: 11 ounces 

Dimensions: 185cm x 80cm

Specific features: Soft and stretchy fabric combined with antimicrobial properties to keep odors at bay. Classic standard shape.

Best use: A great all-round liner for any conditions

Description: This Expander Travel Sleeping Bag liner is made from a soft and stretchy polyester cotton mix fabric, which is less restrictive and warmer than cotton. The fabric stretches as you move so if you’ve ever felt constricted in a mummy-shaped liner then this one could be just what you’re looking for.

The antimicrobial protection means the liner stays fresh and odor-free for longer. This would also be perfect for using on long-haul flights. Some users did not find this as breathable as other liners, so this might not be the best choice for hotter climates.

Check the price on Amazon

Why do you need a sleeping bag liner?

Sleeping bag liners are generally considered to be indispensable these days and are usually near the top of the list of essentials for a seasoned camper. They’re great for a wide variety of trips, and are popular with many non-campers too. If you’re not sure why you might need one, here’s some reasons to invest:

Increase the warmth rating of your sleeping bag: If you’ve invested in a great sleeping bag to use in spring and summer, you might be a bit hesitant to say ‘yes’ to that fall camping trip with some old college friends. If you’re cold at night then you’re pretty much guaranteed a bad night’s sleep. But with a sleeping bag liner, that doesn’t have to be the case. Pop a medium or heavyweight liner in your sleeping bag and you instantly increase the warmth rating of your sleeping bag. Some liners add an amazing 25F of extra heat to your sleeping bag!

Provides an easily washable barrier between you and your sleeping bag: You probably change your bed linen at home every week or so, but most sleeping bags go for months without being washed. Camping, backpacking and traveling all expose the fabric of your sleeping bag to a whole host of possible contaminants: perspiration, mud, dust and insects to name just a few. Many people also find the standard polyester lining of most sleeping bags quite cold against their skin. Using a washable liner is a great way of making sure that your sleeping bag is kept clean and you get that fresh sheet feeling away from home. When you get back from your trip all you need to do it pop it in the wash and pack it away for next time.

In tropical countries, can be used on its own to protect against biting insects: It can be a toss-up between feeling too hot sleeping under a sheet, or taking the sheet off and getting bitten by insects all night long. There’s a great range of liners that are now made specifically for use in tropical climates. The fabric of these is designed to wick excess moisture away from your body as you sleep, leaving you feeling cool and refreshed come morning. Sleeping under a liner also protects you from biting insects, with some liners even coming pre-treated with insect repellent and antimicrobial finishes.

Use in hostels or hotels to increase comfort and familiarity: Many budget hostels charge for the use of bed sheets, so if you’re on a budget, using a sleeping bag liner can be a really economical way too save a bit of money along the way. Also, budget hotels and hostels may not always have the same standards of hygiene that you might want, so by taking a liner you can be sure that your sheet is always clean. It also means you can be in control of the quality, some people prefer soft cotton sheets whilst others like silk. If you take a sleeping bag liner in your preferred fabric, you will always have some comfort and familiarity with you, wherever you are.

Can be used on a long-haul flight instead of an airline blanket: The blankets provided by airlines are often small and difficult to tuck around yourself so you can stay warm. Given that the air-conditioning on most planes will be set pretty cold, you might find it difficult to sleep. If you pop a fleece liner in your hand luggage, you can wrap up nice and warm without worrying about your blankets falling off while you sleep.

What features should I look for in my sleeping bag liner?

There are so many different liners to choose from that sometimes it can be difficult to decide. There’s a few important features that you will want to make note of though, including:


The shape you decide to go for will depend mostly on what you want to use the sleeping bag liner for. Sleeping bag liners come in a range of shapes, including:

  • Standard – straight sides designed to fit a rectangular sleeping bag and can work as a lightweight summer sheet on their own.
  • Standard, long – this standard shaped liner will be cut to a longer length, for taller individuals.
  • Mummy – best for the majority of modern sleeping bags; this liner will be widest at the shoulders, and taper to a narrower foot. Designed to fit inside popular mummy-shaped sleeping bags.
  • Hooded mummy – the same shape as a mummy liner, but with the addition of a hood.
  • Traveler – this liner is similar in shape to the standard, but comes with a pillow pocket which you can insert your pillow into.
  • Double – this is a standard cut liner, but designed for use by two people either in a double bed, or in two sleeping bags zipped together.


There’s a wide range of fabrics available for sleeping bag liners these days, which will be determined by what you want to use the bag for. Lighter liners designed for warmer climates will generally be made of cotton, silk or Coolmax. Liners for colder weather will usually be made of polyester, fleece or Thermolite. The evolution of sleeping bag liners has led to some great advances in the fabrics they are made of, with Coolmax and Thermolite being excellent examples.

Coolmax is an engineered polyester fiber which has improved breathability over natural fibers like cotton. It also has fantastic moisture management, meaning you will wake up feeling cool, combined with quick dry time when you wash the liner. It also moves perspiration away from the body, to the outer surface of the fabric where it can evaporate.

Thermolite, on the other end of the warmth scale, is a hollow core fiber that provides an amazing amount insulation for its weight, whilst also remaining breathable, so you wake up feeling fresh. The hollow fibers trap air which creates the insulating layer around your body.

Weight and size

The weight and size of your sleeping bag liner will in part be defined by your intended use. Liners which offer more insulation will obviously weigh that bit more, whilst lighter liners designed for summer will take up less space.

That said, the majority of liners these days come with stuff sacks and do not take up much room in your pack at all.
If you’re planning on camping out in fall or winter, then you will want the maximum warmth rating possible.


Summer sleeping bag liners won’t come with a hood, but many liners for fall and winter do have the option of a hood. Some people like these because they allow for a bit more insulation as you can tuck them around your head for extra warmth. Other people find them constrictive, so determine whether this is an option you might like.

Bear in mind you can always leave the hood down if you buy a liner with one, but you can’t add one on! Many sleeping bag liners also come with a drawstring around the top. This is so you can secure it above your shoulders, to avoid the chance of it slipping down in the night.

So now you know a little bit more about the variety of sleeping bag liners out there, let’s take a look at some of the choices out there.

Which sleeping bag liner is the perfect addition to your backpack?

Now that you know a little bit more about sleeping bag liners, you can see there’s a wide range out there with many different options. In order to find the right one for you, it’s important to think about where you’re heading and what the conditions will be like. If you’re keen on winter camping then a heavier liner with a higher warmth rating will suit you best.

Likewise, if you’re off to the tropics, then maybe a Coolmax liner with insect protection is just what you’re looking for. Rest assured that whatever your next destination, there will be a sleeping bag liner to perfectly match your needs. If we’ve missed out your favorite liner, please let us know in the comments section.

4 thoughts on “Sea to Summit Sleeping Bag Liners: Every Adventure Will Be Covered”

  1. I have only used Thermolite sleeping bag liner for a couple of times now, but I can honestly say that it is really a great buy. It made a huge difference and improvement in my camping trips. It kept me warm all night and I can sleep soundly whenever I use it.

  2. I personally love CoolMax liner, but your article made me curious about Expander travel liner so I will definitely check that out. As for CoolMax, it is actually quite nice and gives you plenty of leg room. The pillow pocket is a great plus too. Over-all, it is worth the price.

  3. Absolutely! That is a great liner that definitely does its job. The pillow pocket gives you a little storage room for smaller items, which is always a bonus.


Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.