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Base Layers

(408 products)
Products (408)
Sort: Best Match
    Top Rated
    REI Co-opMidweight Base Layer Half-Zip Top - Men's
    $19.83 - $41.89
    Save 30% - 66%
    compared to  $59.95
    143 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    REI Co-opMidweight Long-Sleeve Base Layer Top - Women's
    $26.83 - $38.39
    Save 30% - 51%
    compared to  $54.95
    249 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    Top Rated
    REI Co-opMerino 185 Long-Sleeve Base Layer Top - Men's
    $29.83 - $79.95
    177 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Top Rated
    REI Co-opMerino 185 Long-Sleeve Half-Zip Base Layer Top - Men's
    $29.83 - $89.95
    102 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Top Rated
    REI Co-opMidweight Long-Sleeve Base Layer Top - Men's
    $26.83 - $38.39
    Save 30% - 51%
    compared to  $54.95
    156 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    REI Co-opMidweight Base Layer Tights - Women's
    $26.83 - $38.39
    Save 30% - 51%
    compared to  $54.95
    93 reviews with an average rating of 4.1 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus, Petite
    SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Women's
    $44.83 - $90.00
    121 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    REI Co-opMidweight Base Layer Half-Zip Top - Women's
    $19.83 - $41.89
    Save 30% - 66%
    compared to  $59.95
    140 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    Top Rated
    Arc'teryxIonia Merino Wool Base Layer Top - Men's
    $63.93
    Save 28%
    compared to  $90.00
    40 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 - Men's
    $51.83 - $105.00
    134 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    Top Rated
    REI Co-opMerino 185 Long-Sleeve Half-Zip Base Layer Top - Women's
    $39.83 - $89.95
    102 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
  • Sale Ends Sep 1
    Top Rated
    REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Women's
    $27.89
    Save 30%
    compared to  $39.95
    19 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    SmartwoolClassic All-Season Merino T-Shirt - Women's
    $39.83 - $80.00
    88 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    REI Co-opMerino 185 Base Layer Top - Women's
    $34.83 - $69.95
    50 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    Top Rated
    REI Co-opMidweight Base Layer Crew Top - Kids'
    $23.93 - $34.95
    5 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    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
  • Sale Ends Sep 1
    Top Rated
    REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Men's
    $27.89
    Save 30%
    compared to  $39.95
    9 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    Top Rated
    Arc'teryxIonia Merino Wool Base Layer Hoody - Men's
    $98.93
    Save 29%
    compared to  $140.00
    50 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Women's
    $81.73
    Save 28%
    compared to  $115.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    367 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    REI OUTLET
    Top Rated
    SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Men's
    $44.83 - $90.00
    66 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    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
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Women's
    $115.00
    1149 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    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
    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
    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
    SmartwoolClassic Thermal Merino Base Layer Bottoms - Women's
    $81.73
    Save 28%
    compared to  $115.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    247 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Plus, Regular
    REI OUTLET
  • Sale Ends Sep 1
    Top Rated
    REI Co-opLightweight Base Layer Bottoms - Men's
    $27.89
    Save 30%
    compared to  $39.95
    11 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    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
    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
  • Sale Ends Sep 1
    Top Rated
    REI Co-opLightweight Crew Base Layer Top - Women's
    $20.89
    Save 30%
    compared to  $29.95
    9 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
1–30 of 408 products
Sort: Best Match

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