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  • New Arrivals

Smartwool
Classic Thermal Merino Baselayer Bottom - Women's

3.9565217391304346 out of 5 stars
23 Reviews
Current price: $57.50 - $63.25 Original price: $115.00
Up to 50% off
Color:Black Deco Floral

Size:

Size Chart

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Classic Thermal Merino Bottom delivers breathable warmth for winter adventures

What Our Gearhead® Experts Are Saying:


“These baselayers are my go-to when the temps drop below freezing. They’re soft, warm, and never itchy. Even after a full day of touring, they wick sweat like a champ and still smell fresh enough for the après.”


When the air turns crisp and the trail dusts over with frost, we rely on the Smartwool Classic Thermal Merino Baselayer Bottom for unmatched warmth and comfort. Crafted from 100% merino wool, this heavyweight knit regulates temperature naturally—keeping us warm during dawn starts yet breathable when the day heats up.


Merino’s soft, itch-free fibers wick moisture away and resist odors, making these bottoms perfect for back-to-back ski days or multi-day winter treks. The interlock knit enhances stretch and durability, while flat merrow seams and a merino-lined waistband prevent chafing for all-day ease. Whether layering under ski pants or wearing solo at camp, this baselayer keeps us cozy, dry, and ready for anything the cold brings.


Details

  • Warm merino baselayer bottom for winter hikes and ski days
  • 100% merino wool provides natural temperature regulation
  • Soft interlock knit adds stretch and structure for lasting comfort
  • Moisture-wicking and odor-resistant fibers keep you fresh longer
  • Flat seams and elastic waistband reduce friction and irritation
  • Slim fit layers easily under shells or snow pants
  • Item #SWL01F3
Material
100% merino wool
Insulation Weight
midweight (250gm)
Fit
slim
Style
tights
Anti-Odor
natural attribute of merino wool
Claimed Weight
7.3oz
Activity
ski, snowboard
Manufacturer Warranty
2 years

Overall Rating

4 based on 23 ratings

Review Summary

1 Stars - 1 reviews
2 Stars - 3 reviews
3 Stars - 3 reviews
4 Stars - 5 reviews
5 Stars - 11 reviews

Fits True To Size

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Runs smallTrue to sizeRuns large

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2 out of 5 stars

March 3, 2026

Not durable

Familiarity:
I've used it several times

The seams on these thermal bottoms started unraveling after the second wash. I own other wool items and I know how to wash them and to not put them in the dryer so having these fall apart so fast was disappointing.

Marcy R
Backcountry.com

Originally reviewed on Backcountry.com

3 out of 5 stars

December 23, 2025

Fist time having thermals

Familiarity:
I've used it several times

I bought these thermals for a trip in upstate NY and they hold up pretty well. I know wear them casually on frigid days and they word very well. The Merino wool seems to get a littel scratchy the more you throw it in the wash though.

Therm101
Backcountry.com

Originally reviewed on Backcountry.com

5 out of 5 stars

November 29, 2025

Never seen a cold sheep

Familiarity:
I've put it through the wringer

If you're planning any travel above 60 degrees north latitude in the winter, plan to bring along your Smartwool thermals. You'll be glad you did. The Smartwool products are more durable than any other merino wool products that I have tried. I have worn the thermals under a dry suit in icy cold rivers and under my clothing on land. I love the comfort.

Boreal Migrant
Backcountry.com

Originally reviewed on Backcountry.com

5 out of 5 stars

January 7, 2025

Keeps You Warm When It's Cold Outside

Familiarity:
I've used it several times

I wore these for a couple runs when our temps dropped under 20. Very comfortable and wind resistant.

JoMom
Backcountry.com

Originally reviewed on Backcountry.com

4 out of 5 stars

January 7, 2025

Warm but didn't last

Familiarity:
I've used it once or twice and have initial impressions

Seems didn't last. Super warm and worn a few times while adventuring with littles but the seems in multiple spots came unraveled.

Brigitte S
Backcountry.com

Originally reviewed on Backcountry.com

4 out of 5 stars

December 29, 2024

I’m a dude, and it looks great on me

I want pink, but they didn’t have that in men’s. I’m 5’8, 165 pounds, and I bought an XL, which is a little bit baggy so I would probably get a large next time.

user image
Cyrus D
Backcountry.com

Originally reviewed on Backcountry.com

5 out of 5 stars

November 19, 2024

Super warm thermal leggings!

Familiarity:
I've used it once or twice and have initial impressions

Bought these to have for when it is cold and to keep me warm when camping during winter. I did a lot of research before I purchased these. They are pricey, but worth it. First of all they are thicker and the fit is perfect. They are also flattering and not so thin which allows me to wear them as normal winter leggings as well. Also as pjs around the house during winter too. I loved them so much I decided to buy two more pairs and the base layer tops to match. If you are able to afford these and want thermal base layers that last then these I highly recommend. I’m 5’6, weigh 133 lbs, 30 inch lower waist and a medium fits me perfect.

Andreana
Backcountry.com

Originally reviewed on Backcountry.com

5 out of 5 stars

September 15, 2024

True to size

Familiarity:
I've used it several times

They are high waisted and true to fit. I'm a curvy woman and they fit very comfortably. I wore these under my jeans in Japan in January. They kept me warm and they are oder repellent which is nice while traveling. Highly recommend.

Christina D
Backcountry.com

Originally reviewed on Backcountry.com

5 out of 5 stars

April 9, 2024

In love!

Familiarity:
I've put it through the wringer

I usually struggle to find the perfect fit in bottom base layers, but I was pleasantly surprised to find these fit like a glove right out of the box. I have a bigger bum and run into the issue of layers either being too snug at the waist or too loose at the thighs, but I did not run into this issue at all with these. I wear them casually after a day on the slopes as well and can absolutely see myself wearing them camping, hiking, and in just about any outdoor scenario where the temps drop!

Catherine N
Backcountry.com

Originally reviewed on Backcountry.com

3 out of 5 stars

April 4, 2024

Low rise

The fabric is nice. Unfortunately these are low rise and definitely made for someone with a flat butt. Nice and long though which is what I like. Couldn't keep them though due to that low rise.

Lauren
Backcountry.com

Originally reviewed on Backcountry.com