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Men's Underwear

(163 products)
Products (163)
Sort: Best Match
    Top Rated
    ExOfficioGive-N-Go 2.0 Boxer Briefs - Men's
    $19.73
    Save 34%
    compared to  $30.00
    962 reviews with an average rating of 4.6 out of 5 stars
    Size Type:
    Regular, Big
    REI OUTLET
    Top Rated
    REI Co-opMidweight Long-Sleeve Base Layer Top - Men's
    $37.93 - $54.95
    192 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
    $34.73 - $54.73
    Save 30% - 56%
    compared to  $79.00
    41 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI OUTLET
    REI Co-opHeavyweight Merino Long-Sleeve Base Layer Crew Top - Men's
    $69.93 - $99.95
    39 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
    tasc PerformanceElevation Merino T-Shirt - Men's
    $34.73 - $54.73
    Save 30% - 56%
    compared to  $79.00
    51 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI OUTLET
    Top Rated
    REI Co-opHeavyweight Merino Base Layer Bottoms - Men's
    $69.93 - $99.95
    17 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
    REI Co-opMerino 185 Base Layer Bottoms - Men's
    $55.93 - $79.95
    158 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI Co-opMidweight Base Layer Bottoms - Men's
    $54.95
    100 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Men's
    $44.95
    32 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
  • Sale Ends Today
    Free CountryForce Grid Fleece Base Layer Bottoms - Men's
    $21.73
    Save 51%
    compared to  $45.00
    18 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Big, Regular
    REI OUTLET
  • Sale Ends Today
    Free CountryCloud Knit Base Layer Bottoms - Men's
    $19.73
    Save 50%
    compared to  $40.00
    3 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Big, Regular
    REI OUTLET
    Top Rated
    SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Men's
    $66.93 - $100.00
    99 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI Co-opMerino Boxers - Men's
    $39.95
    76 reviews with an average rating of 4.3 out of 5 stars
    Size Type:
    Regular, Big
    REI Co-opEveryday Boxers - Men's
    $24.95
    135 reviews with an average rating of 4.2 out of 5 stars
    Size Type:
    Regular, Big
    Top Rated
    REI Co-opLightweight Base Layer Bottoms - Men's
    $44.95
    26 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
    220 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI Co-opEveryday Boxer Briefs - Men's
    $24.95
    159 reviews with an average rating of 4.2 out of 5 stars
    Size Type:
    Regular, Big
  • Sale Ends Today
    Free CountryCloud Knit Crewneck Base Layer Top - Men's
    $19.73
    Save 50%
    compared to  $40.00
    8 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Big, Regular
    REI OUTLET
  • Sale Ends Today
    Top Rated
    Free CountryForce Grid Fleece Base Layer Top - Men's
    $21.73
    Save 51%
    compared to  $45.00
    17 reviews with an average rating of 4.9 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Big, Regular
    REI OUTLET
    Top Rated
    REI Co-opMerino 185 Long-Sleeve Half-Zip Base Layer Top - Men's
    $62.93 - $89.95
    120 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
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    Get 5% on all REI Co-op purchases plus the 10% Co-op Member Reward you earn on eligible full-price purchases.



    Terms apply
    Top Rated
    REI Co-opMidweight Base Layer Half-Zip Top - Men's
    $41.93 - $59.95
    177 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 Base Layer Bottoms - Men's
    $125.00
    638 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    Top Rated
    SaxxQuest Boxer Briefs - Men's
    $24.73
    Save 27%
    compared to  $34.00
    6 reviews with an average rating of 4.8 out of 5 stars
    Size Type:
    Regular
    REI OUTLET
    Top Rated
    IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Men's
    $69.93 - $120.00
    212 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    Top Rated
    REI Co-opLightweight Crew Base Layer Top - Men's
    $14.83 - $34.95
    26 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    SaxxVolt Breathable Mesh Boxer Briefs - Men's
    $26.73
    Save 23%
    compared to  $35.00
    8 reviews with an average rating of 4.3 out of 5 stars
    Size Type:
    Regular, Big
    REI OUTLET
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Men's
    $125.00
    1510 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    Top Rated
    ExOfficioGive-N-Go 2.0 Boxer Briefs - Men's
    $22.73
    Save 24%
    compared to  $30.00
    2980 reviews with an average rating of 4.5 out of 5 stars
    Size Type:
    Regular
    REI OUTLET
    Top Rated
    ExOfficio9" GNG Sport 2.0 Boxer Briefs - Men's
    $24.73
    Save 27%
    compared to  $34.00
    535 reviews with an average rating of 4.7 out of 5 stars
    Size Type:
    Regular
    REI OUTLET
  • Sale Ends Today
    StanceGood Times Boxer Briefs - Men's - Package of 2
    $21.73
    Save 51%
    compared to  $45.00
    2 reviews with an average rating of 5.0 out of 5 stars
    Size Type:
    Regular
    REI OUTLET
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