Smartwool Merino 250 Base Layer Bottoms

Attention to detail & overall practicality make the Smartwool 250 Base Layer Bottoms one of our favorite pair of base layer bottoms.


Smartwool is a staple in the Merino wool industry, and their 250 Base Layer bottoms are one of our favorites. The thick, 250 GSM midweight fabric will keep you warm in the winter but still offers plenty of breathability to keep you dry.

Although these leggings may seem basic, they are highly-engineered with your comfort in mind. The gusseted crotch, flatlock seams, Merino-covered waistband, and technical fit provide a luxurious next-to-skin feel. In other words, the last thing you want in the backcountry is for your bottoms to be irritable, right?

Note: These aren’t super form-fitting as you may imagine standard leggings to be. We view them more like long underwear. However, they are relatively supportive and offer plenty of room for movement. If you have questions about sizing – or about Smartwool apparel, in general – head over to our Smartwool company spotlight page.

To sum up, while they are not our first choice as standalone leggings, they definitely are one of our top picks as a base layer.

Smartwool Merino 250 Base Layer Bottoms

Specs & Features:

  • 100% Merino wool construction
  • 250 GSM midweight-to-heavyweight fabric thickness
  • Slim-to-regular fit (size up for a more relaxed fit)
  • Merino-lined waistband for reduced rubbing around stomach
  • Gusseted crotch, flatlock seams, and improved design minimizes irritation
  • 3 colors available (black, heather gray, navy)


  • Industry-leading thermoregulation properties
  • Technical design improves comfort (see specs and features above)
  • Trusted Merino wool brand with reliable customer service & warranty


  • May stretch with improper care (check out our complete Merino wool care guide for tips)
  • The thicker fabric is relatively slow-drying

Best For:

Adventure | Camping | Hiking | Snowsports

Featured In:

10 Best Long Underwear For Skiing

Helpful Links:

Disclaimer: To maintain genuineness and authenticity, Merino Wool Gear DOES NOT sponsor products. However, as an Amazon Associate, we may earn a commission from qualifying purchases.

Additional information

Merino Percentage

>95% Merino Wool

Fabric Density (gsm)

225 – 265 Midweight


Camping, Winter Sports, Hiking, Adventure, Training

Colors Available

Black, Heather Gray, Navy


Semi-Fitted / Slim