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Lightweight Base Layers

(133 products)
Products (133)
Remove underwear-weight filter:Lightweight
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  • Sale Ends Today
    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
  • Sale Ends Today
    REI Co-opLightweight Half-Zip Base Layer Top - Women's
    $31.39
    Save 30%
    compared to  $44.95
    1 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
  • Sale Ends Today
    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
    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:
    Big, Regular
    REI OUTLET
  • Sale Ends Today
    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
    Top Rated
    REI Co-opMerino 185 Long-Sleeve Base Layer Top - Men's
    $79.95
    178 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
  • Sale Ends Today
    Top Rated
    REI Co-opLightweight Crew Base Layer Top - Women's
    $20.89
    Save 30%
    compared to  $29.95
    10 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Women's
    $66.93 - $90.00
    119 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
  • Sale Ends Today
    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
  • Sale Ends Today
    Top Rated
    REI Co-opLightweight Base Layer Bottoms - Infants'/Toddlers'
    $13.89
    Save 30%
    compared to  $19.95
    8 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
  • Sale Ends Today
    Top Rated
    REI Co-opLightweight Crew Base Layer Top - Infants'/Toddlers'
    $13.89
    Save 30%
    compared to  $19.95
    10 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    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
    REI OUTLET
  • Sale Ends Today
    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
  • Sale Ends Today
    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
  • Sale Ends Today
    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
    tasc PerformanceElevation Merino Base Layer Bottoms - Men's
    $49.73
    Save 37%
    compared to  $79.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    31 reviews with an average rating of 3.8 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Big, Regular
    REI OUTLET
  • Sale Ends Today
    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 All-Season Merino Long-Sleeve Base Layer Top - Men's
    $44.83 - $90.00
    67 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    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
    Kari TraaRose High-Waisted Base Layer Pants - Women's
    $54.83 - $130.00
    24 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    SmartwoolClassic All-Season Merino T-Shirt - Women's
    $80.00
    88 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    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-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
    Arc'teryxLana Merino Wool Crew Base Layer Top - Women's
    $59.93
    Save 33%
    compared to  $90.00
    4 reviews with an average rating of 2.3 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    SmartwoolIntraknit Thermal Merino Base Layer Bottoms - Women's
    $92.73
    Save 28%
    compared to  $130.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    27 reviews with an average rating of 4.3 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    REI OUTLET
    REI Co-opMerino 185 Base Layer Top - Women's
    $69.95
    50 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    Top Rated
    Black DiamondSolution 150 Merino Base Layer Bottoms - Women's
    $79.73
    Save 27%
    compared to  $110.00
    Members use code LABORDAY2025 for an extra 20% off at REI Outlet
    31 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    REI OUTLET
    SmartwoolClassic All-Season Merino T-Shirt - Men's
    $80.00
    80 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Top Rated
    Arc'teryxRho LT Crew Neck Base Layer Top - Men's
    $100.00
    28 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    SmartwoolClassic All-Season Merino Base Layer Bottoms - Women's
    $90.00
    16 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
1–30 of 133 products
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