Icebreaker Women's Merino 250 Vertex Thermal Leggings review: a toasty base layer for chilly conditions

These comfortable, breathable thermal leggings will keep you dry heading uphill and warm for the ski down

Icebreaker merino thermal leggings
(Image: © Icebreaker)

Advnture Verdict

These are comfortable, breathable midweight thermal leggings that provide an excellent base layer to keep you warm and dry during cold winter hikes, snowshoeing and skiing.


  • +

    Comfortable and warm

  • +

    Natural fabric is breathable and fast drying

  • +

    Odor resistant


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  • -

    Run a little large

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Icebreaker Women's Merino 250 Vertex Thermal Leggings: first impressions 

On the rack, these soft, thermal leggings make a comfortable and effective midweight base layer for winter hiking and snowshoeing, skiing and snowboarding, and cold weather camping. Superior warmth and breathability make them good for cold weather conditions while natural merino wool provides odor protection and breathability when you’re working up a sweat.

The fabric is completely non-itchy and a gusseted crotch and flatlock seams prevent rubbing or chafing. You can expect to move freely in these leggings when you’re skiing or climbing a steep slope.

The snug fit is not skin tight but allows for layering and these would provide all the protection you need in winter under a pair of windproof and waterproof pants. Though they’ll mostly be hidden from view as base layer, the fun pattern is nice if you do decide to wear them lounging around the house.


• RRP: $130 / £100
• Sizes available: XS - XL
• Materials: Merino (100%)
• Colors:  Black/heather jet, Snow/heather jet
• Best use: Winter hiking, camping, snowshoeing, skiing 

Icebreaker Women's Merino 250 Vertex Thermal Leggings: on the trails 

Icebreaker women's thermal leggings

These soft, thermal leggings make a comfortable and effective midweight base layer for winter hiking and snowshoeing, skiing and snowboarding, and cold weather camping (Image credit: Icebreaker)

I love a good, soft pair of thermal leggings under my ski pants for very cold days of alpine skiing and snowshoeing, and at night for cold weather camping, and these leggings really cover all the bases.

First, they feature a really fun pattern called “fractured landscapes” which makes a nice change from my usual all-black leggings. Then, there’s the comfort factor – even though they are 100% merino wool, there’s not a hint of an itch in them and none of the seams or waistband rub (even though the elastic waistband looks like it will cut into the skin). I found them really comfortable for hiking, sleeping in my sleeping bag and hanging out around the house.

The fabric doesn't feel as stretchy as a lot of fabrics containing spandex but they don’t restrict movement whatsoever. They provide tons of warmth and I worked up a sweat in them and found them very breathable, but depending on conditions where you are you might want a lightweight pair if you’re planning on exerting yourself. They are also quick drying which is a huge plus for me, and the all-natural fabric means they don’t get stinky.

I tested a small which would usually be a perfect fit for me and found these to be slightly on the large side. There’s just a little more loose fabric than I’d want for warmth and for layering – they bunched up a little when I pulled my waterproof hiking pants on over them, but once I got them on they worked well as a layer. I’d probably size down for my next pair.

They’re certainly a more expensive pair of thermal leggings but they’re good quality and should last you a long time with proper care. I have found that my favorite merino wool base layers do develop small holes and I think as a fabric, it can be a bit less durable, but since it boasts superior odor-protection, if you don’t wash them a lot they will last.

They’re a little too pajama-like for me to wear them out and about, but I love these as a base layer and for lounging.

Here’s how they performed:


A little on the loose/large side for me. If you are smaller-framed, you may want to size down to make it easier to layer these. 


Snug but not skin-tight. Since these are meant to be layered and seem really stretchy, I think they could get away with skin tight fit but perhaps a smaller size is all I need. 


Very cosy and comfortable in terms of movement, I had no rubbing anywhere and was happy there was no scratchy wool feel. 

Temperature regulation 

These are very warm leggings good for cold conditions. They are also breathable and fast drying so I didn’t get too hot in them working up a sweat. That said, if you’re looking for thermal leggings for strenuous activity in winter, you might prefer a lightweight version. 


Merino wool is great for breathability and I totally trust these to keep me dry even on the stepper slopes. 


Remains to be seen, though I’ve found that some other merino wool base layers don’t hold up quite as well. That said, they don’t get stinky easily and without frequent washing, you shouldn’t have a problem. 

Here’s where we tested the Icebreaker Women's Merino 250 Vertex Thermal Leggings: 

Ben Arthur, otherwise known as The Cobbler, is a distinctive peak at the head of Loch Lomond. The true summit requires some technical scrambling that many choose to miss.

Julia Clarke

Julia Clarke is a staff writer for and the author of the book Restorative Yoga for Beginners. She loves to explore mountains on foot, bike, skis and belay and then recover on the the yoga mat. Julia graduated with a degree in journalism in 2004 and spent eight years working as a radio presenter in Kansas City, Vermont, Boston and New York City before discovering the joys of the Rocky Mountains. She then detoured west to Colorado and enjoyed 11 years teaching yoga in Vail before returning to her hometown of Glasgow, Scotland in 2020 to focus on family and writing.