Best base layers for women UK 2023: stay cosy and comfortable with thermal base layers for outdoor adventures
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Thermals, long johns, base layers – whatever you want to call them, there’s nothing like a warm layer worn next to the skin to help keep the chill of colder weather at bay.
Whether you’re off skiing, hiking or cold weather camping, layering up is the best way to trap in heat and keep cosy in the great outdoors – and a good layering system starts next to the skin with a quality base layer top and leggings set.
Thermals should hug your body without feeling too restrictive around the waistband, ankles, neck or sleeves.
Some base layers are stretchier than others – we reckoned thermals with some stretch offered more warmth on test, as there’s no empty space between the fabric and your skin for the cold to creep in.
Thermal tops usually have a crew neck or a high, zipped neck – the latter can double up as a neck warmer, and some tops also sport hoodies for extra warmth. We also look for base layers that use ‘flatlock’ sticking – this avoids any rubbing against your skin.
Best ladies’ thermals at a glance:
- Best 100% merino wool/best on test: Icebreaker Merino Oasis top and leggings
- Best for style points: Arc’teryx Motus AR long sleeve top
- Best for running: Runderwear long sleeve top
- Best winter bottoms: Jack Wolfskin Iseler Tights W
- Best on a budget: Alpkit Koulin Trail long sleeve top
- Best for comfort: Acai Winter top and bottoms
- Best for posture: CEP Wingtech short sleeve top
- Best for skiing: Haglofs Actives Wool top and bottoms
- Best for hiking: Paramo Grid Technic long sleeve topÂ
What material should your thermals be made of?
Many base layers are made with synthetic materials such as polyester, but the best (but often the most expensive) base layers are made with a percentage of merino wool – merino is very warm but still highly breathable, and is great at wicking away sweat.
It also has naturally antimicrobial properties, making it perfect if you’re getting active or for when you’re heading into the backcountry without a shower in sight.
Bamboo base layers are more recent arrivals on the market – they’re also a great choice, as they’re soft to wear, antimicrobial and more eco-friendly to produce than synthetic materials.
What do the numbers on thermals mean?
You may see base layers listed with a number, such as 140 or 220 – this refers to their weight in grams, and the higher the number, the warmer, but heavier, the base layer.
We tested out the latest base layers on cold weather hikes and compared them for warmth, breathability and comfort. Pair with a great fleece for guaranteed cosiness.
Get kitted out for all of your camping adventures
We have detailed guides to the best hiking backpacks here, and the best backpacking tents for your adventures here. Want to steady your stride? These are the best walking poles for hiking.
Keep it comfy with the best camping folding chairs, and sleep on the best air beds around, as listed here. And keep things illuminated with a great camping head torch.
After waterproof trousers? These are the best women’s ones.
Base layers are what Icebreaker do best, and they’re always some of the top-performing designs when we test out base layers.
£75 (top), £60 (bottoms)
If you want to invest in a great set of thermal underwear, our pick of the pack are their Oasis base layer top and their Everyday Thermal leggings.
Slip them on and the first thing you’ll notice is how deliciously soft their 100% Merino wool make-up feels against the skin.
The Oasis’ 200g weight is a good warmth to weight ratio for most outdoor adventures, and the Thermal leggings live up to their name, keeping you delightfully warm even on winter hikes and ski adventures.
Icebreaker’s merino layers are worth the spend, and will last you for years without losing their shape or their warming abilities.
The bottoms are available here.
