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Underwear

(560 products)
Products (560)
Sort: Best Match
    SmartwoolClassic All-Season Merino T-Shirt - Men's
    $39.83 - $80.00
    80 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Top Rated
    REI Co-opMidweight Base Layer Bottoms - Kids'
    $23.93 - $34.95
    8 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
  • Sale Ends Sep 1
    Top Rated
    REI Co-opLightweight Crew Base Layer Top - Men's
    $20.89
    Save 30%
    compared to  $29.95
    17 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    tasc PerformanceElevation Merino T-Shirt - Men's
    $49.73
    Save 37%
    compared to  $79.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    38 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI OUTLET
  • Sale Ends Sep 1
    Top Rated
    REI Co-opLightweight Base Layer Tights - Women's
    $27.89
    Save 30%
    compared to  $39.95
    7 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    REI Co-opActive Bikini Underwear - Women's
    $19.95
    51 reviews with an average rating of 3.3 out of 5 stars
    Size Type:
    Regular, Plus
    SmartwoolClassic Thermal Merino Base Layer Quarter-Zip - Women's
    $89.73
    Save 25%
    compared to  $120.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    0 reviews
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    REI OUTLET
    Kari TraaRose Half-Zip Base Layer Top - Women's
    $59.83 - $140.00
    30 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    REI Co-opMerino 185 Base Layer Bottoms - Men's
    $79.95
    129 reviews with an average rating of 4.3 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Ortovox185 Merino Rock'n'wool Long-Sleeve Base Layer Top - Men's
    $54.83
    Save 50%
    compared to  $110.00
    10 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
  • Sale Ends Sep 1
    Top Rated
    REI Co-opLightweight Half-Zip Base Layer Top - Men's
    $31.39
    Save 30%
    compared to  $44.95
    5 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    REI Co-opActive Hipster Underwear - Women's
    $18.95
    35 reviews with an average rating of 3.8 out of 5 stars
    Size Type:
    Regular, Plus
    REI Co-opMerino 185 Long-Sleeve Base Layer Top - Women's
    $79.95
    199 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    Top Rated
    SmartwoolClassic Thermal Merino Base Layer Bottoms - Men's
    $115.00
    617 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
  • Sale Ends Sep 1
    Top Rated
    REI Co-opLightweight Base Layer Crew Top - Kids'
    $20.89
    Save 30%
    compared to  $29.95
    12 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Men's
    $115.00
    1506 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    Top Rated
    IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Women's
    $49.83 - $105.00
    135 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    Top Rated
    SmartwoolClassic Thermal Merino Quarter-Zip Base Layer Top - Women's
    $120.00
    30 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    Top Rated
    Arc'teryxRho LT Zip-Neck Base Layer Top - Men's
    $120.00
    91 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Top Rated
    PatagoniaCapilene Midweight Base Layer Bottoms - Men's
    $59.93 - $89.00
    56 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Kids'
    $44.73
    Save 31%
    compared to  $65.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    5 reviews with an average rating of 3.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
    Arc'teryxRho Base Layer Bottoms - Women's
    $24.83 - $100.00
    17 reviews with an average rating of 4.1 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    REI Co-opActive Thong Underwear - Women's
    $14.95
    20 reviews with an average rating of 4.4 out of 5 stars
    Size Type:
    Regular, Plus
    Kari TraaFryd Base Layer Top - Women's
    $29.83 - $65.00
    21 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
  • Sale Ends Sep 1
    Top Rated
    REI Co-opLightweight Base Layer Bottoms - Kids'
    $20.89
    Save 30%
    compared to  $29.95
    9 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    Top Rated
    PatagoniaCapilene Midweight Crew Base Layer Top - Men's
    $59.93 - $89.00
    79 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    tasc PerformanceElevation Merino Base Layer Bottoms - Women's
    $49.73
    Save 37%
    compared to  $79.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    53 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    REI OUTLET
    REI Co-opMerino 185 Base Layer Top - Women's Plus Sizes
    $34.83 - $69.95
    21 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Plus
    Terramar2.0 Cloud Nine Half-Zip Base Layer Top - Women's
    $34.73
    Save 30%
    compared to  $50.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    0 reviews
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
    Top Rated
    Kari TraaRose High-Waisted Base Layer Pants - Women's
    $54.83 - $130.00
    14 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
31–60 of 560 products
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