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Smartwool Merino Wool Liner Socks

Smartwool Merino Wool Sock Liners

Humphrey Weightman convinced me to try wool sock liners. Well not exactly, but that was the end result.

We were having an email exchange over  New Years about the gear and clothing he thinks is best suited for hiking across Scotland in early May. In his opinion, wool is better for socks and undergarments that synthetics because it accumulates less smell over time. I figured that a man like Humphrey, who has hiked across Scotland multiple times with a plush bear, is a man worth listening too.

So when it came time to try on socks to wear with my new trail runner based shoe system, I bought a whole bunch of different wool socks and tried them out instead of just using the dozens of REI polypro liners socks I already own. They’re good for wearing under heavy wool socks in leather or plastic mountaineering boots, but I needed something thinner for a trail shoe.

The truth is that I wanted a sock that would still keep my feet warm after a good soaking and still dry quickly. What I found out was counter-intuitive. The thinner the wool sock, the warmer it felt when wet in cool weather.

I’m not sure why this is. I suppose it could be that my body heat can warm a thin wool sock faster than a thick wool sock and dry it out faster. Regardless, I plan on using the Smartwool Merino Sock Liner on my Challenge hike across Scotland in May.

In addition to their warmth, I haven’t experienced any friction hiking with these socks in trail runners, even when they’ve been both soaked for extended periods of time. They also have flat seams along the toes making them more comfortable and easily reversible for multi-day trips.

As claimed, these socks do not accumulate smells when worn for multiple days at a time, and being black, they look like the day they were bought after being laundered. The truth is, I wear the same clothes for a 5 or more days at a time on longer backpacking trips, and clothes that can take that kind of punishment and still look like new after a wash are keepers.

They’re even comfortable with dress shoes.

Disclosure: The author owns this product and purchased it using their own funds.


  1. Merino wool is certainly the way to go. I've worn merino wool socks on all my trips from a few days to several months for many years. In Scotland's wet climate they're ideal. So are merino wool base layers. On my last three Challenges I've worn the same merino top the whole way, without washing, and it was still comfortable at the finish – and didn't stink!

  2. Although I've used synthetic capilene base layers for years, I may have to try a merino top before the challenge based on your recommendation. I've heard that there are no laundromats in Montrose. That could be bad since I have to use public transportation to get down to Edinburgh.

  3. I haven't tried out the Merino wool liner socks yet but do own several pairs of other SmartWool socks. A couple of them are heavy, well cushioned hiking socks for cold weather. The other pairs are quite thin and designed for light hiking, running, cycling and everyday use. You can decide on the amount of cushion, or bulk, you want in the sock based on your activity, and then browse through SmartWool's large selection.

    You may have found that a thin sock keeps your feet warmer and that is because the properties of Merino wool make it possible. These properties include extremely fine and curly fibers that create a tighter, more durable weave with tiny air pockets that allow your feet to breathe and regulate your body temperature. Merino wool wicks away sweat in its vapor stage so your feet stay dry and odor free because bacteria do not have a chance to build up. Merino wool also quickly releases moisture from external sources, such as water. These are great reasons to wear them on longer hiking trips, especially in wet climates.

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