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Men's Underwear

(170 products)
Products (170)
Sort: Best Match
    REI Co-opMerino Boxer Briefs - Men's
    $29.89
    Save 25%
    compared to  $39.95
    Sale Ends Nov 23
    126 reviews with an average rating of 4.2 out of 5 stars
    Size Type:
    Regular, Big
    REI Co-opLightweight Base Layer Bottoms - Men's
    $29.93 - $33.69
    Save 25% - 33%
    compared to  $44.95
    Top Rated
    32 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    REI Co-opMerino 185 Base Layer Bottoms - Men's
    $63.69
    Save 25%
    compared to  $84.95
    Sale Ends Nov 23
    Top Rated
    5 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Men's
    $29.93 - $33.69
    Save 25% - 33%
    compared to  $44.95
    Top Rated
    53 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 - Men's
    $93.69
    Save 25%
    compared to  $125.00
    Sale Ends Nov 30
    Top Rated
    764 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    REI Co-opMerino 185 Long-Sleeve Crew Base Layer Top - Men's
    $63.69
    Save 25%
    compared to  $84.95
    Sale Ends Nov 23
    Top Rated
    5 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    SmartwoolIntraknit Boxer Briefs - Boxed - Men's
    $41.19
    Save 25%
    compared to  $55.00
    Sale Ends Nov 23
    0 reviews
    Size Type:
    Regular, Big
    REI Co-opMidweight Long-Sleeve Crew Base Layer Top - Men's
    $48.69
    Save 25%
    compared to  $64.95
    Sale Ends Nov 23
    Top Rated
    8 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    tasc PerformanceElevation Merino Base Layer Bottoms - Men's
    $54.73
    Save 30%
    compared to  $79.00
    REI Outlet
    45 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Free CountryForce Grid Fleece Base Layer Bottoms - Men's
    $26.73
    Save 33%
    compared to  $40.00
    REI Outlet
    23 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    tasc PerformanceElevation Merino T-Shirt - Men's
    $54.73
    Save 30%
    compared to  $79.00
    REI Outlet
    57 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Men's
    $93.69
    Save 25%
    compared to  $125.00
    Sale Ends Nov 30
    Top Rated
    1116 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Men's
    $59.83 - $89.99
    Save 25% - 50%
    compared to  $120.00
    Top Rated
    114 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    REI Co-opMidweight Base Layer Bottoms - Men's
    $48.69
    Save 25%
    compared to  $64.95
    Sale Ends Nov 23
    Top Rated
    6 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    SmartwoolIntraknit Thermal Max Merino Quarter-Zip Base Layer Top - Men's
    $107.87
    Save 30%
    compared to  $155.00
    REI Outlet
    0 reviews
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big
    REI Co-opMerino Boxers - Men's
    $29.89
    Save 25%
    compared to  $39.95
    Sale Ends Nov 23
    88 reviews with an average rating of 4.4 out of 5 stars
    Size Type:
    Regular, Big
    REI Co-opMerino 250 Base Layer Bottoms - Men's
    $78.69
    Save 25%
    compared to  $104.95
    Sale Ends Nov 23
    0 reviews
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
    SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Men's
    $74.99
    Save 25%
    compared to  $100.00
    Sale Ends Nov 30
    Top Rated
    547 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI Co-opEveryday Boxers - Men's
    $18.69
    Save 25%
    compared to  $24.95
    Sale Ends Nov 23
    153 reviews with an average rating of 4.2 out of 5 stars
    Size Type:
    Regular, Big
    SmartwoolIntraknit Thermal Merino Crew Base Layer Top - Men's
    $92.73 - $96.73
    Save 25% - 28%
    compared to  $130.00
    REI Outlet
    251 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    REI Co-opLightweight Half-Zip Base Layer Top - Men's
    $34.93 - $37.39
    Save 25% - 30%
    compared to  $49.95
    25 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    StanceButter Blend Boxers - Men's
    $19.97
    Save 37%
    compared to  $32.00
    REI Outlet
    7 reviews with an average rating of 3.9 out of 5 stars
    Size Type:
    Regular, Big
    REI Co-opMerino 250 Half-Zip Base Layer Top - Men's
    $82.39
    Save 25%
    compared to  $109.95
    Sale Ends Nov 23
    1 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
    REI Co-opEveryday Boxer Briefs - Men's
    $18.69
    Save 25%
    compared to  $24.95
    Sale Ends Nov 23
    170 reviews with an average rating of 4.1 out of 5 stars
    Size Type:
    Regular, Big
    REI Co-opMerino 250 Long-Sleeve Crew Base Layer Top - Men's
    $78.69
    Save 25%
    compared to  $104.95
    Sale Ends Nov 23
    1 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
    SmartwoolMerino Print Boxer Briefs - Men's
    $37.49
    Save 25%
    compared to  $50.00
    Sale Ends Nov 23
    New arrival
    2 reviews with an average rating of 5.0 out of 5 stars
    Size Type:
    Regular, Big
  • Text reads ‘happening now!’ over an image of the R E I Co-op Mastercard.

    $130 in value

    Get $30 in card rewards when you’re approved by Nov 23. Plus, earn a $100 REI gift card after your first qualifying purchase.

    Terms apply

    Free CountryForce Grid Fleece Base Layer Top - Men's
    $26.73
    Save 33%
    compared to  $40.00
    REI Outlet
    Top Rated
    19 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    StanceUtopia Boxer Briefs - Men's
    $14.97
    Save 40%
    compared to  $25.00
    REI Outlet
    0 reviews
    Size Type:
    Regular
    SaxxQuest Quick-Dry Boxer Briefs - Men's
    $26.99
    Save 25%
    compared to  $36.00
    Sale Ends Nov 23
    Top Rated
    62 reviews with an average rating of 4.7 out of 5 stars
    Size Type:
    Regular, Big
    REI Co-opMerino 185 Crew Base Layer Top - Men's
    $56.19
    Save 25%
    compared to  $74.95
    Sale Ends Nov 23
    4 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
Sort: Best Match

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