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Outdoor Underwear

(517 products)

Products (517)

Sort: Best Match

tasc PerformanceElevation Merino Base Layer Bottoms - Women's
$49.73
Save 37%
compared to $79.00
53 reviews with an average rating of 4.2 out of 5 stars
REI OUTLET
SmartwoolIntraknit Active Base Layer Bottoms - Women's
$79.93
Save 27%
compared to $110.00
6 reviews with an average rating of 4.3 out of 5 stars
Nani SwimwearUinta Base Layer Top - Women's
$29.83
Save 62%
compared to $80.00
13 reviews with an average rating of 4.5 out of 5 stars
Top Rated
REI Co-opLightweight Crew Base Layer Top - Men's
$29.95
10 reviews with an average rating of 4.6 out of 5 stars
SmartwoolClassic Thermal Merino Base Layer Bottoms - Women's
$110.00 - $115.00
736 reviews with an average rating of 4.5 out of 5 stars
Top Rated
Panache SportEndurance Wired Sports Bra
$51.93 - $79.00
10 reviews with an average rating of 4.5 out of 5 stars
BrooksConvertible 2.0 Sports Bra
$60.00
98 reviews with an average rating of 3.6 out of 5 stars
tasc PerformanceElevation Merino T-Shirt - Men's
$49.73
Save 37%
compared to $79.00
38 reviews with an average rating of 4.2 out of 5 stars
REI OUTLET
REI Co-opMidweight Base Layer Bottoms - Men's
$54.95
77 reviews with an average rating of 4.4 out of 5 stars
tasc PerformanceElevation Merino Base Layer Bottoms - Men's
$49.73
Save 37%
compared to $79.00
31 reviews with an average rating of 3.8 out of 5 stars
REI OUTLET
Panache SportBoundless Non Wired Sports Bra
$76.00
18 reviews with an average rating of 4.3 out of 5 stars
REI Co-opLightweight Base Layer Tights - Women's Plus Sizes
$9.83
Save 75%
compared to $39.95
12 reviews with an average rating of 4.3 out of 5 stars
Top Rated
REI Co-opMidweight Base Layer Crew Top - Kids'
$34.95
5 reviews with an average rating of 5.0 out of 5 stars
Arc'teryxRho Merino Wool Zip-Neck Base Layer Top - Men's
$69.83 - $98.83
Save 29% - 50%
compared to $140.00
10 reviews with an average rating of 4.2 out of 5 stars
NikeIndy High-Support Bra
$50.00
35 reviews with an average rating of 3.9 out of 5 stars
REI Co-opMidweight Base Layer Tights - Women's
$54.95
91 reviews with an average rating of 4.1 out of 5 stars
NikeIndy Light Support Bra
$38.00
32 reviews with an average rating of 4.1 out of 5 stars
Top Rated
SmartwoolClassic Thermal Merino Quarter-Zip Base Layer Top - Women's
$59.83 - $120.00
28 reviews with an average rating of 4.8 out of 5 stars
Top Rated
REI Co-opMidweight Base Layer Bottoms - Kids'
$34.95
8 reviews with an average rating of 4.6 out of 5 stars
Top Rated
Beyond YogaSpacedye Slim Racerback Bra
$62.00
185 reviews with an average rating of 4.5 out of 5 stars
Top Rated
REI Co-opMerino 185 Long-Sleeve Half-Zip Base Layer Top - Men's
$62.93 - $89.95
102 reviews with an average rating of 4.6 out of 5 stars
Helly HansenVerglas Half-Zip Top - Women's
$63.73
Save 25%
compared to $85.00
1 reviews with an average rating of 5.0 out of 5 stars
REI OUTLET
Top Rated
REI Co-opActive Thong Underwear - Women's
$14.95
18 reviews with an average rating of 4.6 out of 5 stars
CraftActive Intensity Base Layer - Women's
$36.73
Save 43%
compared to $64.95
4 reviews with an average rating of 3.0 out of 5 stars
REI OUTLET
Top Rated
SmartwoolClassic Thermal Merino Base Layer Bottoms - Men's
$115.00
615 reviews with an average rating of 4.7 out of 5 stars
Top Rated
SmartwoolClassic Thermal Merino Base Layer Bottoms - Kids'
$48.73
Save 25%
compared to $65.00
52 reviews with an average rating of 4.7 out of 5 stars
REI OUTLET
Top Rated
RHONERevive Longline Bra
$45.93 - $58.00
67 reviews with an average rating of 4.9 out of 5 stars
OnPerformance Flex Bra
$75.00
4 reviews with an average rating of 5.0 out of 5 stars
rabbitUtiliBRA-vo Sports Bra
$50.00
19 reviews with an average rating of 4.4 out of 5 stars
OiselleHi Twenty Bra
$58.00 - $68.00
1 reviews with an average rating of 5.0 out of 5 stars

31–60 of 517 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