Best base layer 2024: Add warmth without the bulk

In winter, having the best base layer is essential for outdoor activities, ensuring comfort in fluctuating temperatures. Whether hiking or camping, these close-fitting layers provide insulation and sweat-wicking properties for optimal performance.

Designed to be stretchy and comfortable, base layers facilitate seamless layering without adding bulk. With our roundup of the top base layers, you'll be well-equipped for any chilly adventure, allowing you to enjoy the outdoors without worrying about discomfort.

As you've probably guessed, the base layer is the first of many thin layers you can put on or take off as needed to maintain a comfortable temperature. As such, if you're out hiking, you could add a fleece jacket with one of the best waterproof jackets on top to ensure you have plenty of options depending on the weather and how much you exert yourself.

Our current top choice for the base layer is Arc’teryx's Rho Hybrid Half Zip top. It's extremely versatile and comfortable – a superb base layer overall. If you need to wick sweat fast, you can't go wrong with the Helly Hansen LIFA top listed in second place. If you're on a tight budget but don't want to compromise too much on quality, check out the BAM Reflex Bamboo Base Layer.

Best base layers to buy right now

Best overall

We have previously waxed lyrical about Arc’Teryx base layers, purely because they appear to have been born out of the coldest conditions and can therefore withstand anything most ‘regular’ winters can throw at them.

The RHO LT Hoody is part of the lightweight collection, so feels featherweight against the skin and almost invisible when layered up as part of a proper outdoors layering system. The brushed stretch polyester is also a nice touch for added comfort.

Arguably its most unique selling point is the built in neck warmer, which can also extend to become a hood or full coverage balaclava during those whiteout days where protection from the elements is vital.

It’s up there with the best thanks to a few careful considered features, such as the easy access smartphone pocket on the chest and the athletic fit that stretches and moves with the body, making it great for running, climbing and a number of other outdoor pursuits.

Best moisture management

We found that the Helly Hansen LIFA Merino Lightweight Half Zip Baselayer excels in comfort, fit, and performance. This lightweight baselayer combines synthetic LIFA fibres with merino wool for effective moisture management and lightweight warmth.

Design features include a soft-backed neck zip, flatlocked seams, and a snug fit. It performed well in cold conditions, keeping us dry and comfortable during high-output activities.

While it lacks thumb loops, it remains odour-resistant and durable after multiple uses. Ideal for active outdoor pursuits, it’s a reliable choice for staying warm and dry.

Read our full Helly Hansen LIFA Merino Lightweight Half Zip Baselayer review.

Best budget

BAM specialises in clothing made from bamboo, often with other fibres blended in for maximum comfort, durability and performance while still being as eco-friendly as possible (this brand is responsible for some of the best yoga pants around). Of its base layer options, our pick is the Reflex, which uses bamboo jersey with its soft, breathable, sweat-wicking and anti-bacterial.

The design is cut longer in the body and arms to ensure everything stays covered even when you're moving around a lot – there are even thumb loops for when it's chilly. Flatlock seams and raglan sleeves minimise chafing. Even though it's longer to keep your lower back warm, BAM's top is more tight fitting than other base layers in this guide.

Best for hot weather

ThruDark's short-sleeved base layer caught our attention thanks to its material. Polartec's Delta uses the Fresh Face technology, which is a plant-based, sustainable alternative to traditional textile fresheners and is infused with mint oil to keep you cool even on the hottest of days.

Thanks to the superb moisture-wicking capabilities and more relaxed fit, the Oryon Delta T-Shirt clings less to your body when you sweat. It feels somewhat thicker than other synthetic base layers, but once the temperature starts rising inside and outside the top, you'll soon feel the mint oil-powered cooling kicking in.

Best eco-friendly

There is very little that’s quite as comfortable against the skin as 100 per cent merino wool and this range from UK brand Finisterre is fantastic as either a loose-fitting base layer or as a casual T-shirt.

It is only available in navy or olive, which limits the outfit paring somewhat, and it isn’t as athletic in its fit as others, so some may not want to purchase it as part of a complex layering system for climbing or winter walking, but it’s a great casual option.

Finisterre gear is built to last and carefully considered to reduce the impact of fashion on the plant, and the Seeker Merino is no exception. However, 100 per cent merino wool is delicate by its very nature, so requires careful washing and drying habits.

On that subject, merino has natural sweat-wicking and anti-odour properties, but this wasn’t up there with the most breathable base layers we have tested. As a properly technical garment, it’s not top of the pile, but as something more fashionable, easy to live with a exceptionally warm on a winter’s day, it is fantastic.

Best merino

Icebreaker's Tech Lite is a classic among frequent travellers and 'speedpackers' thanks to its odour-resistant capabilities and the fact it can be wrung out in a sink and dried in hours. It works great as a regular T-shirt (it's not as figure-hugging as most base layers), and, between you and us, you can wear an Icebreaker Tech Lite for days on end without getting too whiffy.

The only drawback is that Merino does lack longevity, which is why most brands don't get much beyond 50%. Expect this top to thin out and get holes after about a year or two of heavy use (top tip: keep it for hikes and holidays only). 

How to choose the best base layer for you

Choosing the best base layer is crucial for comfort and performance during outdoor activities.

Merino wool offers warmth, moisture-wicking, and odour resistance, while synthetic fibres like polyester are durable and quick-drying. Bamboo blends are eco-friendly and soft but may not dry as quickly.

Select a weight that matches your activity and climate. Lightweight base layers are ideal for high-intensity activities, such as hiking and trail running or mild weather, while midweight or heavyweight options provide extra warmth for cold conditions.

Consider features like thumb loops, half-zip designs for ventilation, and flatlock seams for added comfort. These small details can significantly enhance your experience.

Also, check the durability and care instructions. Some materials are more robust and easier to maintain, extending the lifespan of your base layer.

Reviewer panel

Jamie Carter

Jamie is a freelance journalist, copywriter and author with 20 years of experience. He spends most of his time travelling and staring at the skies (via a telescope), often in the cold, so he inevitably ends up testing base layers. It's only natural he writes about them, too.

Ruth Hamilton

Former Outdoor and Wellness channel editor, Ruth knows a thing or two about kit for an active lifestyle. Whether that's walking trousers, flip-flops or torches for lighting the way, Ruth has put it through its paces.

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