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Base Layers

(329 products)

Products (329)

Sort: Best Match

Top Rated
REI Co-opMerino 185 Long-Sleeve Base Layer Top - Men's Tall Sizes
$79.95
11 reviews with an average rating of 4.8 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Tall
Arms of Andes300 Alpaca Wool Long-Sleeve Crew Base Layer Top - Men's
$64.83 - $69.83
Save 50%
compared to $130.00 - $140.00
9 reviews with an average rating of 3.7 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
Icebreaker125 ZoneKnit Crewe Base Layer Shirt - Men's
$84.73
Save 26%
compared to $115.00
7 reviews with an average rating of 4.4 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
REI OUTLET
Free CountryCloud Knit Crewneck Base Layer Top - Men's
$26.73
Save 33%
compared to $40.00
10 reviews with an average rating of 4.0 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Big, Regular
REI OUTLET
Ortovox120 Comp Light Short Base Layer Pants - Men's
$70.00
3 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
PatagoniaCapilene Midweight Crew Base Layer Top - Kids'
$28.73
Save 26%
compared to $39.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
Arms of Andes160 Ultralight Alpaca Wool Long-Sleeve Base Layer Shirt - Men's
$44.83
Save 50%
compared to $90.00
13 reviews with an average rating of 3.6 out of 5 stars
Underwear Weight:
Ultralightweight
Size Type:
Regular
Arms of Andes300 Lightweight Alpaca Wool Base Layer Leggings - Men's
$56.83
Save 50%
compared to $115.00
16 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Big
Arms of Andes160 Ultralight Alpaca Wool Base Layer Leggings - Men's
$46.83
Save 50%
compared to $95.00
2 reviews with an average rating of 3.0 out of 5 stars
Underwear Weight:
Ultralightweight
Size Type:
Regular, Big
Top Rated
StioBasis PeakWool Midweight Half-Zip Base Layer Top - Men's
$159.00
Add to cart to see price
7 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
Arc'teryxRho SV Zip-Neck Base Layer Top - Men's
$140.00
14 reviews with an average rating of 3.6 out of 5 stars
Underwear Weight:
Heavyweight
Size Type:
Regular
PatagoniaCapilene Thermal Weight Zip-Neck Top - Men's
$115.00
25 reviews with an average rating of 3.9 out of 5 stars
Underwear Weight:
Heavyweight
Size Type:
Regular
SmartwoolIntraknit Thermal Merino Colorblock Crew Base Layer Top - Men's
$77.83 - $130.00
12 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
PatagoniaCapilene Thermal Weight Crewneck Base Layer Top - Men's
$73.73
Save 25%
compared to $99.00
0 reviews
Underwear Weight:
Heavyweight
Size Type:
Regular
REI OUTLET
PatagoniaCapilene Midweight Base Layer Bottoms - Kids'
$28.73
Save 26%
compared to $39.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
SmartwoolClassic Thermal Merino Base Layer Hoodie - Men's
$108.73
Save 25%
compared to $145.00
3 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
REI OUTLET
PatagoniaCapilene Thermal Weight Long-Underwear Bottoms - Men's
$99.00
16 reviews with an average rating of 4.1 out of 5 stars
Underwear Weight:
Heavyweight
Size Type:
Regular, Big
REI Co-opMerino 185 Base Layer Bottoms - Men's Tall Sizes
$79.95
17 reviews with an average rating of 3.9 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Tall, Big
Kari TraaSmekker Half-Zip Base Layer Top - Women's
$140.00
21 reviews with an average rating of 4.0 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
SmartwoolIntraknit Thermal Merino Crew Base Layer Top - Men's
$92.73
Save 28%
compared to $130.00
136 reviews with an average rating of 4.4 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
REI OUTLET
SmartwoolIntraknit Thermal Merino Colorblock Quarter-Zip Base Layer Top - Women's
$83.83 - $140.00
7 reviews with an average rating of 4.3 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
Kari TraaKlara High-Waisted Base Layer Pants - Women's
$62.73 - $66.73
Save 25% - 30%
compared to $90.00
14 reviews with an average rating of 3.9 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
REI OUTLET
SmartwoolClassic Thermal Merino Colorblock Crew Base Layer Top - Women's
$77.83
Save 40%
compared to $130.00
2 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
Arms of Andes300 Lightweight Alpaca Wool Half-Zip Base Layer Top - Men's
$71.83
Save 50%
compared to $145.00
16 reviews with an average rating of 3.9 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
Top Rated
SmartwoolClassic All-Season Merino Quarter-Zip Base Layer Top - Women's
$69.73
Save 26%
compared to $95.00
6 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
REI OUTLET
Kari TraaAnna High-Waist Base Layer Pants - Women's
$110.00
1 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
KUHLReactiv Lite Grid Long-Sleeve Crew Base Layer Top - Women's
$53.83
Save 50%
compared to $109.00
3 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
PatagoniaCapilene Midweight Zip-Neck Base Layer Top - Women's
$49.83 - $99.00
30 reviews with an average rating of 4.3 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
KUHLReactiv Lite Grid Quarter-Zip Base Layer Top - Men's
$119.00
12 reviews with an average rating of 4.3 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
StioBasis PeakWool Midweight Base Layer Tights - Men's
$149.00
Add to cart to see price
4 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Big
Ortovox185 Rock'N'Wool Long-Sleeve Base Layer Top - Men's
$120.00 - $130.00
0 reviews
Underwear Weight:
Lightweight
Size Type:
Regular, Big
SmartwoolIntraknit Thermal Max Merino Quarter-Zip Base Layer Top - Men's
$99.93 - $155.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular, Big
SmartwoolClassic Thermal Merino Base Layer Quarter-Zip - Kids'
$49.73
Save 28%
compared to $70.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
KUHLReactiv Lite Grid Long-Sleeve Crew Base Layer Top - Men's
$109.00
11 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
Kari TraaAnna Long-Sleeve Base Layer Top - Women's
$54.83
Save 50%
compared to $110.00
3 reviews with an average rating of 3.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
New arrival
SmartwoolIntraknit Merino 3/4 Base Layer Bottoms - Women's
$89.73
Save 25%
compared to $120.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
Top Rated
Free CountryForce Grid Fleece Base Layer Top - Men's
$29.73
Save 33%
compared to $45.00
17 reviews with an average rating of 4.9 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Big
REI OUTLET
New arrival
SmartwoolClassic Thermal Merino Colorblock Crew Base Layer Top - Men's
$96.73
Save 25%
compared to $130.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular, Big
REI OUTLET
SmartwoolIntraknit AS Merino Base Layer Bottoms - Women's
$125.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular
Arms of Andes160 Ultralight Alpaca Wool Base Layer Leggings - Men's
$41.83
Save 50%
compared to $85.00
5 reviews with an average rating of 3.8 out of 5 stars
Underwear Weight:
Ultralightweight
Size Type:
Regular
SENIQWool Sculpt Merino Mock-Neck Long-Sleeve Base Layer Shirt - Women's
$99.93 - $128.00
2 reviews with an average rating of 3.0 out of 5 stars
Underwear Weight:
Heavyweight
Size Type:
Regular
Helly HansenLIFA Merino Midweight Graphic Base Layer Pants - Women's
$79.73
Save 27%
compared to $110.00
1 reviews with an average rating of 1.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
SmartwoolIntraknit AS Merino Base Layer Crew Top - Men's
$125.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular, Big
Top Rated
SmartwoolClassic All-Season Merino Quarter-Zip Base Layer Top - Women's
$105.00
6 reviews with an average rating of 4.5 out of 5 stars
Size Type:
Regular
SmartwoolClassic All-Season Merino 3/4 Base Layer Bottoms - Men's
$85.00
5 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
HalfdaysFay Midweight Merino Base Layer Top - Women's
$64.83 - $130.00
38 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
SmartwoolIntraknit Thermal Merino Crew Base Layer Top - Women's
$96.73
Save 25%
compared to $130.00
130 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
Top Rated
IcebreakerMerino 200 Oasis Base Layer Leggings with Fly - Men's
$120.00
86 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
Top Rated
Arc'teryxRho Insulated 3/4 Base Layer Bottoms - Men's
$159.73
Save 20%
compared to $200.00
13 reviews with an average rating of 4.6 out of 5 stars
Underwear Weight:
Heavyweight
Size Type:
Big, Regular
REI OUTLET
Arc'teryxRho SV Base Layer Bottoms - Men's
$120.00
Add to cart to see price
1 reviews with an average rating of 2.0 out of 5 stars
Underwear Weight:
Heavyweight
Size Type:
Regular, Big
Ortovox120 Comp Light Base Layer Hoody - Men's
$120.00
2 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
Top Rated
HalfdaysHallie Midweight Merino Base Layer Leggings - Women's
$64.83 - $130.00
30 reviews with an average rating of 4.6 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
Free CountryCloud Knit Base Layer Bottoms - Men's
$26.73
Save 33%
compared to $40.00
3 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Big
REI OUTLET
SmartwoolIntraknit Thermal Merino Base Layer Bottoms - Women's
$150.00
30 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
Kari TraaSaga Base Layer Pants - Women's
$59.83
Save 50%
compared to $120.00
0 reviews
Underwear Weight:
Heavyweight
Size Type:
Regular
Hot ChillysOriginals Solid Base Layer Crew - Kids'
$34.73
Save 26%
compared to $47.50
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
Top Rated
SmartwoolClassic Thermal Merino Base Layer Quarter-Zip - Men's
$89.73
Save 25%
compared to $120.00
57 reviews with an average rating of 4.6 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
REI OUTLET
Free CountryForce Grid Fleece Base Layer Top - Women's
$34.73
Save 36%
compared to $55.00
7 reviews with an average rating of 4.4 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Plus
REI OUTLET
Hot ChillysOriginals Print Base Layer Pants - Kids'
$39.73
Save 27%
compared to $55.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
SmartwoolIntraknit Thermal Merino Base Layer Bottoms - Women's
$92.73
Save 28%
compared to $130.00
30 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
REI OUTLET
Mountain HardwearUp First Tech Fleece Base Layer Bottoms - Men's
$74.73
Save 25%
compared to $100.00
4 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
REI OUTLET
Top Rated
Icebreaker200 Oasis Long-Sleeve Half-Zip Base Layer Top - Men's
$130.00
35 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
Top Rated
SmartwoolClassic Thermal Merino Crew Base Layer Top - Women's
$81.73 - $84.73
Save 26% - 28%
compared to $115.00
436 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
Top Rated
IcebreakerMerino 200 ZoneKnit Long-Sleeve Half-Zip Base Layer Top - Men's
$119.73
Save 25%
compared to $160.00
8 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
REI OUTLET
PatagoniaCapilene Thermal Weight Zip-Neck Base Layer Top - Women's
$69.73
Save 36%
compared to $109.00
17 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Heavyweight
Size Type:
Regular
REI OUTLET
SmartwoolIntraknit AS Merino Base Layer Bottoms - Men's
$125.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular, Big
Free CountryForce Grid Fleece Base Layer Bottoms - Men's
$29.73
Save 33%
compared to $45.00
19 reviews with an average rating of 4.1 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
REI OUTLET
SmartwoolIntraknit Thermal Merino Base Layer Bottoms - Men's
$150.00
32 reviews with an average rating of 4.3 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
StioBasisPeak Wool Midweight Half-Zip Base Layer Top - Women's
$95.40
Add to cart to see price
3 reviews with an average rating of 4.3 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
Hot ChillysOriginals Print Base Layer Crew - Kids'
$39.73
Save 27%
compared to $55.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
SaxxRoast Master Midweight Long-Sleeve Crew Base Layer Top - Men's
$47.73
Save 36%
compared to $75.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Big
REI OUTLET
IcebreakerMerino 200 Oasis Long-Sleeve Crewe Base Layer Top - Women's
$59.83 - $120.00
1 reviews with an average rating of 4.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
Top Rated
SmartwoolClassic Thermal Merino Base Layer Bottoms - Kids'
$65.00
72 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
Helly HansenLIFA Merino Midweight Graphic Crew Base Layer - Women's
$79.73
Save 27%
compared to $110.00
4 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
Helly HansenGraphic Lifa Merino Base Layer Set - Kids'
$93.73
Save 25%
compared to $125.00
1 reviews with an average rating of 1.0 out of 5 stars
Underwear Weight:
Heavyweight
Size Type:
Regular
REI OUTLET
Top Rated
SmartwoolClassic Thermal Merino Crew Base Layer Top - Men's
$84.73
Save 26%
compared to $115.00
317 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
REI OUTLET
Arms of Andes300 Lightweight Alpaca Wool 3/4 Base Layer Leggings - Men's
$54.83
Save 50%
compared to $110.00
1 reviews with an average rating of 4.0 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
Ortovox185 Rock'N'Wool Short Base Layer Pants - Men's
$100.00 - $110.00
0 reviews
Underwear Weight:
Lightweight
Size Type:
Regular, Big
Top Rated
Arc'teryxKyanite Base Layer Bottoms - Women's
$120.00
Add to cart to see price
27 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Heavyweight
Size Type:
Regular, Plus
Kari TraaEmbla Wool Long-Sleeve Base Layer Top - Women's
$44.83 - $90.00
0 reviews
Underwear Weight:
Ultralightweight
Size Type:
Regular
Top Rated
Arc'teryxRho Zip-Neck Base Layer Top - Women's
$120.00
52 reviews with an average rating of 4.8 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Plus
Ortovox185 Rock'N'Wool Zip Neck Base Layer Top - Men's
$130.00
0 reviews
Underwear Weight:
Lightweight
Size Type:
Regular, Big
Ortovox230 Competition Long-Sleeve Base Layer Top - Men's
$110.00
2 reviews with an average rating of 3.5 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
SmartwoolClassic Thermal Merino Crew Base Layer Top - Kids'
$65.00
6 reviews with an average rating of 3.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
StioBasisPeak Wool Midweight Base Layer Tights - Women's
$149.00
Add to cart to see price
5 reviews with an average rating of 4.4 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
SmartwoolIntraknit Active Base Layer Bottoms - Men's
$81.73
Save 25%
compared to $110.00
4 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
REI OUTLET
Top Rated
SmartwoolClassic Thermal Merino Base Layer Bottoms - Kids'
$48.73
Save 25%
compared to $65.00
47 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
Helly HansenLIFA Merino Midweight 2-In-1 Graphic Half-Zip Base Layer Top - Women's
$86.73
Save 27%
compared to $120.00
1 reviews with an average rating of 4.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
REI OUTLET
Kari TraaLucie Base Layer Pants - Women's
$58.73
Save 26%
compared to $80.00
6 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
REI OUTLET
Arc'teryxRho LT Base Layer Bottoms - Men's
$79.73
Save 20%
compared to $100.00
0 reviews
Underwear Weight:
Midweight
Size Type:
Big
REI OUTLET

91–180 of 329 products

Sort: Best Match

Related Expert Advice articles

What material is best?

Wool is moisture-wicking and odor-resistant, while synthetic fabrics are more durable and less expensive.

Match the temp to the trek

Lightweight layers are best for moderate to cool temperatures. Midweight layers are best for cold temperatures. Heavyweight layers are best for below-freezing temperatures.

Find your fit

To be able to wick sweat efficiently, your next-to-skin layer needs to actually be next to your skin. A comfortably snug fit everywhere is your goal.

Read full article: How to Choose Base Layers