The best 3-season sleeping bags reviewed (2023)

Every day of good adventure should end with a well-earned, restful sleep – not shivering until 3am in a woefully thin cocoon. That’s why finding the right sleeping bag is essential. A high-quality 3-season sleeping bag will guarantee a good night’s sleep for most of the year. It’ll keep you warm, cosy and comfortable, and ensure you’re well-rested for the adventures ahead.

A 3-season sleeping bag is the most popular sleeping bag in terms of seasonality because it is designed for use between early spring and late autumn. Compared to a winter sleeping bag, they're pretty versatile. But covering a broad seasonal range, there are naturally a great many types and styles of 3-season sleeping bag.

We've conducted our latest 3-season sleeping bag group test, including models from a range of price points and designs in order to establish which is best for you.

Our shortlist

Sea to Summit Spark SpIII - Best in Test

Snugpak Softie 6 - Best Value

Sierra Designs Cloud 800 20 Degree - Best ventilation

Rab Alpine 600 - Best for warmth

Mammut Perform Down -7C - Best for comfort

Therm-a-Rest Parsec 20F/-6C - Best for lightness

Mountain Equipment Glacier 450 - Best for durability

The North Face Blue Kazoo Eco - Best for sustainability

The best 3-season sleeping bags

What to look for in a 3-season sleeping bag

Construction

Most down bags use a box-wall construction, which traps the fill inside brick-shaped baffles. Larger baffles give more space for insulation to loft, but smaller baffles can stop the fill from migrating. Angled baffles and zoned construction can reduce cold spots. Synthetic bags often use a baffle-free construction that features a single sheet of insulation.

Cut

Most bags are available in different lengths or widths, as well as women-specific fits. ‘Performance mummy’ bags are slim fitting and highly tapered to save weight and boost warmth. Some may find them restrictive though.

Fabric

Shells and linings are usually made from nylon, though cheaper bags use polyester. Durable water-resistant (DWR) coatings are often applied to protect the fill. Areas particularly prone to damp, like the base, foot and hood may have additional protection.

Fill

Down offers superior warmth-to-weight compared to synthetic fills, but synthetic bags are cheaper, easier to look after and remain warm when wet. Some down bags now have hydrophobic fills or coatings to improve performance in damp conditions. Down quality is measured by fill power (FP), but don’t forget to also look at the total weight of down fill in a bag when assessing its warmth.

Hood

An insulated and closefitting hood makes a big difference in cold conditions. Look for a bag with hood drawcords so you can adjust the fit, but ensure they are comfortably placed and easy to use.

Pack size and weight

A lightweight sleeping bag with a small pack size is easier to stash and carry around in your rucksack. Look for a bag with a compression stuffsack to really cinch down the pack size.

Shoulder baffle

A neck or shoulder baffle helps to lock heat in by preventing warm air from escaping around the face.

Storage sack

In addition to a stuffsack, many bags now come with a larger cotton storage sack that allows the bag to loft and breathe when not in use. This prevents musty odours and damage to the fill caused by long-term compression.

Temperature rating

Most bags give a comfort limit, a lower limit and an extreme limit. The comfort and lower limits are the best indicators of a bag’s realistic temperature range, but they should only be used as a guide.

Zip

A full-length zip allows you to vent heat and makes getting in and out easier, though a shorter zip saves weight. Zips usually have a baffle to prevent cold spots, but make sure it doesn’t snag. Note that if you are right-handed, a zip on the left side is generally easier to use and vice versa. If you’re a side sleeper, make sure the zip won’t end up underneath your body, as this can be uncomfortable.

Sleeping bag care and cleaning

Cleaning sleeping bags and storing them correctly when not in use are both very straightforward but need to be done correctly in order to enjoy many years of use. Head to our guide on cleaning and caring for insulated gear to find out how.

How to care for sleeping bags and insulated jackets

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