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Midweight Base Layers

(108 products)
Products (108)
Sort: Best Match
  • Sale Ends May 25
    REI Co-opMidweight Long-Sleeve Base Layer Top - Women's
    $41.19
    Save 25%
    compared to  $54.95
    324 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
  • Sale Ends May 25
    REI Co-opMidweight Base Layer Tights - Women's
    $41.19
    Save 25%
    compared to  $54.95
    126 reviews with an average rating of 4.3 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus, Petite
  • Sale Ends May 25
    Top Rated
    REI Co-opMidweight Long-Sleeve Base Layer Top - Men's
    $41.19
    Save 25%
    compared to  $54.95
    211 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    Top Rated
    SmartwoolClassic Thermal Merino Quarter-Zip Base Layer Top - Women's
    $49.83 - $97.49
    Save 25% - 61%
    compared to  $130.00
    72 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Plus, Regular
  • Sale Ends May 25
    Top Rated
    SmartwoolClassic Thermal Merino Base Layer Bottoms - Men's
    $93.69
    Save 25%
    compared to  $125.00
    647 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
  • Text reads: ‘Anniversary Sale 2026. 25% off’ over a collage of Smartwool long-sleeve shirts and colorful socks.

    Save 25% on all Smartwool clothing

  • Sale Ends May 25
    Top Rated
    SmartwoolClassic Thermal Merino Quarter-Zip Base Layer Top - Men's
    $97.49
    Save 25%
    compared to  $130.00
    61 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 - Men's
    $49.83 - $93.69
    Save 25% - 60%
    compared to  $125.00
    1539 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
  • Sale Ends May 25
    SmartwoolClassic Thermal Merino Base Layer Bottoms - Women's
    $63.49
    Save 44%
    compared to  $115.00
    280 reviews with an average rating of 4.3 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
    SmartwoolIntraknit Thermal Merino Crew Base Layer Top - Women's
    $49.83 - $112.49
    Save 25% - 66%
    compared to  $150.00
    201 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
  • Sale Ends May 25
    Top Rated
    REI Co-opMidweight Base Layer Bottoms - Men's
    $41.19
    Save 25%
    compared to  $54.95
    104 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
  • Sale Ends May 25
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Women's
    $93.69
    Save 25%
    compared to  $125.00
    1222 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
  • Sale Ends May 25
    SmartwoolClassic Thermal Merino Base Layer Bottoms - Women's
    $93.69
    Save 25%
    compared to  $125.00
    769 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    Top Rated
    PatagoniaCapilene Midweight Base Layer Bottoms - Men's
    $70.93
    Save 20%
    compared to  $89.00
    60 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Women's
    $81.73 - $84.73
    Save 26% - 28%
    compared to  $115.00
    440 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
  • Sale Ends May 25
    Top Rated
    REI Co-opMidweight Base Layer Half-Zip Top - Men's
    $44.89
    Save 25%
    compared to  $59.95
    194 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    Top Rated
    REI Co-opMidweight Base Layer Crew Top - Kids'
    $25.93
    Save 25%
    compared to  $34.95
    8 reviews with an average rating of 4.9 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    Top Rated
    REI Co-opMidweight Base Layer Bottoms - Kids'
    $25.93
    Save 25%
    compared to  $34.95
    14 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    Top Rated
    PatagoniaCapilene Midweight Crew Base Layer Top - Women's
    $70.93
    Save 20%
    compared to  $89.00
    52 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    Top Rated
    SmartwoolClassic Thermal Merino Base Layer Quarter-Zip - Men's
    $89.73
    Save 25%
    compared to  $120.00
    61 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    REI OUTLET
  • Sale Ends May 25
    REI Co-opMidweight Base Layer Half-Zip Top - Women's
    $44.89
    Save 25%
    compared to  $59.95
    195 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    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
    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
    SmartwoolClassic Thermal Merino 3/4 Base Layer Bottoms - Men's
    $78.73
    Save 25%
    compared to  $105.00
    0 reviews
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    REI OUTLET
    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
  • Sale Ends May 25
    Top Rated
    IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Men's
    $89.99
    Save 25%
    compared to  $120.00
    231 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Kids'
    $44.73
    Save 25% - 31%
    compared to  $60.00 - $65.00
    7 reviews with an average rating of 3.9 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
  • Limited time only! The R E I Co-op Mastercard.

    Get $130 in value

    When approved for the REI Co-op Mastercard by May 25, you’ll get $30 in card rewards. Plus, you can earn a $100 REI gift card after your first non-REI purchase within 60 days from account opening. Terms apply.

    Top Rated
    REI Co-opMidweight Base Layer Crew Top - Toddlers'
    $17.93
    Save 28%
    compared to  $24.95
    16 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Men's
    $84.73
    Save 26%
    compared to  $115.00
    318 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    REI OUTLET
    Top Rated
    REI Co-opMidweight Base Layer Bottoms - Toddlers'
    $17.93
    Save 28%
    compared to  $24.95
    9 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    PatagoniaCapilene Midweight Zip-Neck Base Layer Top - Women's
    $63.73
    Save 35%
    compared to  $99.00
    30 reviews with an average rating of 4.3 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
Sort: Best Match

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