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Men's Underwear

(158 products)
Products (158)
Sort: Best Match
    SmartwoolActive Boxer Briefs - Men's
    $24.73
    Save 29%
    compared to  $35.00
    0 reviews
    Size Type:
    Regular, Big
    REI OUTLET
    New arrival
    SmartwoolEveryday Merino Boxer Briefs - Men's
    $34.73
    Save 27%
    compared to  $48.00
    0 reviews
    Size Type:
    Regular, Big
    REI OUTLET
    Top Rated
    REI Co-opMidweight Long-Sleeve Base Layer Top - Men's
    $37.93 - $54.95
    198 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    REI Co-opHeavyweight Merino Long-Sleeve Base Layer Crew Top - Men's
    $69.93 - $99.95
    41 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
    Top Rated
    SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Men's
    $66.93 - $100.00
    87 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Top Rated
    REI Co-opHeavyweight Merino Base Layer Bottoms - Men's
    $69.93 - $99.95
    18 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
    tasc PerformanceElevation Merino Base Layer Bottoms - Men's
    $34.73 - $54.73
    Save 30% - 56%
    compared to  $79.00
    42 reviews with an average rating of 4.0 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Big, Regular
    REI OUTLET
    Top Rated
    REI Co-opLightweight Crew Base Layer Top - Men's
    $34.95
    26 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    Top Rated
    REI Co-opMidweight Base Layer Half-Zip Top - Men's
    $41.93 - $59.95
    182 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    New arrival
    SmartwoolMerino Boxer Briefs Boxed - Men's
    $34.73
    Save 27%
    compared to  $48.00
    0 reviews
    Size Type:
    Regular, Big
    REI OUTLET
    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
    REI Co-opMerino Boxer Briefs - Men's
    $39.95
    114 reviews with an average rating of 4.2 out of 5 stars
    Size Type:
    Regular, Big
    Top Rated
    SmartwoolClassic Thermal Merino Base Layer Bottoms - Men's
    $125.00
    640 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
    $125.00
    1513 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    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
    REI Co-opMidweight Base Layer Bottoms - Men's
    $54.95
    101 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    REI Co-opMerino Boxers - Men's
    $39.95
    79 reviews with an average rating of 4.3 out of 5 stars
    Size Type:
    Regular, Big
    REI Co-opMerino 185 Base Layer Bottoms - Men's
    $79.95
    161 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    SaxxQuest Quick-Dry Boxer Briefs - Men's
    $34.00
    0 reviews
    Size Type:
    Regular, Big
    tasc PerformanceElevation Merino T-Shirt - Men's
    $34.73 - $54.73
    Save 30% - 56%
    compared to  $79.00
    52 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI OUTLET
  • Limited-time offer! The REI Co-op Mastercard.

    Get $130 in value

    $30 in card rewards are yours when approved for the REI Co-op Mastercard by Mar 9. Plus, you can earn a $100 REI gift card after your first purchase. Terms apply.

    Top Rated
    REI Co-opMerino 185 Long-Sleeve Half-Zip Base Layer Top - Men's
    $62.93 - $89.95
    124 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Top Rated
    SaxxQuest Boxer Briefs - Men's
    $24.73
    Save 27%
    compared to  $34.00
    7 reviews with an average rating of 4.6 out of 5 stars
    Size Type:
    Regular
    REI OUTLET
    New arrival
    SmartwoolMerino Boxer Briefs - Boxed - Men's
    $50.00
    0 reviews
    Size Type:
    Regular, Big
    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
    PatagoniaCapilene Midweight Crew Base Layer Top - Men's
    $61.93 - $89.00
    89 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    PatagoniaCapilene Midweight Zip-Neck Base Layer Top - Men's
    $68.93 - $99.00
    74 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    Top Rated
    REI Co-opMerino 185 Long-Sleeve Base Layer Top - Men's
    $79.95
    221 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Men's
    $44.95
    36 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    Top Rated
    IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Men's
    $69.93 - $120.00
    220 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    REI Co-opHeavyweight Merino Base Layer Half-Zip Top - Men's
    $72.93 - $104.95
    25 reviews with an average rating of 4.2 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
1–30 of 158 products
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