Review: Smartwool Classic Thermal Merino Base Layer

Could this be the perfect snowsports base layer?

Feature type Review

Read time 5 mins

Published Feb 14, 2023

Author Tammy Esten

Photographer Gaby Thompson

Tammy Esten Tammy is a backcountry snowboarder who lives in Morzine and is the founder of Mint Snowboarding.

Our verdict

Stretchy, comfortable and warm – the Smartwool Classic Thermal has everything you’d want from your new favourite base layer.

RRP £99.99
Material 100% merino wool


  • Long length in the body is great to avoid any cold gaps
  • Not itchy
  • Soft
  • Stretchy
  • The perfect weight to keep you warm but equally remain comfortable whilst doing  sport


  • Only con is the price. But personally I would say it’s well worth it

What I’m Looking For

I LOVE base layers! I run cold, and so living in the French Alps, working and playing daily in the mountains, I demand a lot from my base layers, which get a lot of use. 

Of course it’s all about comfort and warmth when it comes to a good quality base layer. Which fabric and weight I opt for will depend on which sport or activity I am using it for, but as I generally run cold generally speaking I want maximum warmth. In my eyes, simplicity is best, I’m not looking for a fancy design.

I get frustrated when base layers are too short in the sleeve or in the body – there’s nothing worse than a cold gap around your kidneys which can easily be made worse by lots of bending over or wearing a climbing harness. So a close fit is essential, but at the same time it needs to be stretchy to allow for full mobility. Next to the skin, it needs to be soft and non-itchy, particularly on those long extended days.

First impressions

My initial thought was that it this Smartwool base layer has a great shape, with lots of length in the body and sleeves, which will suit me just right. Result! It also has a nice neckline – not too low, nor too high. Which is harder to find than it might seem.

From the moment I put it on, it was perfectly comfortable and soft. It immediately felt like it could become my new best friend. 

It immediately felt like it could become my new best friend

The Test

Running a snowboarding school, I’m up in the mountains every day and often stood around for long periods of time without exerting much energy and then suddenly on the move.

After a couple of shorter test runs, Smartwool’s Classic Thermal Merino Base Layer has become a staple of my mountain setup, which I’ve been using most days for the last couple of months. I’ve taken it on splitboarding morning missions from my front door, all-dayers with friends and also teaching days around Morzine, Avoriaz, les Gets and Chatel as well as just going about my day-to-day life here in the French Alps.

Who is this Base Layer for? 

This is a warm, pretty heavy weight base layer so it’s suitable for any activity in particularly cold conditions. It’s not an activity specific garment, and I would recommend it anything from snowsports, to climbing, mountaineering, winter hiking or wet weather activities, depending on what kind of warmth you need.

Personally I would also wear it day-to-day under a warm jumper, but I am someone who always feels the cold. You can’t beat comfort and warmth no matter what you are doing!

What Stands Out?


It is a thick weight base layer which offers plenty of warmth during lower intensity winter outdoor activities. The perfect under layer to keep you warm on those colder days.

Odour free

Being 100% merino wool, it stays amazingly fresh. I’ve worn it probably too many days in a row to mention and it still doesn’t smell!


This is a big win for me. Having that extra length avoids any cold gaps and it also works great with longer snowsports jackets.


It has a close fitting cut, but at the same time is not too tight. This maximises warmth but also means that the garment gives you all the mobility that you need for whatever activity you use it for. 


Merino base layers are never cheap, but they are worth it if you spend a lot of time in the cold, and you’re looking to maximum warmth in a high quality, durable garment.

I am very much a believer in paying a fair price on products that are built to last. I have had similar quality base layers before that have lasted more than a decade of constant use for six months a year… you can’t grumble at that.


This base layer does everything that it should; offering maximum warmth, comfort and mobility. I couldn’t fault it in any way. 

This really is my new favourite base layer and there is a very strong chance that I’ll be heading straight over to the Smartwool website to invest in another of exactly the same model. No different from someone finding their perfect pair of jeans and straight away buying a second pair! 

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