Skip to search results
loaded 236 results

Long Sleeve Underwear

(236 products)
Products (236)
Sort: Best Match
    Top Rated
    REI Co-opMerino 185 Long-Sleeve Crew Base Layer Top - Men's
    $84.95
    5 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big, Tall
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Women's
    $125.00
    1540 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    Top Rated
    SmartwoolClassic Thermal Merino Base Layer Quarter-Zip - Women's
    $89.97
    Save 30%
    compared to  $130.00
    1100 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
    REI Co-opMerino 250 Long-Sleeve Crew Base Layer Top - Men's
    $104.95
    1 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
    Top Rated
    SmartwoolClassic All-Season Merino Base Layer Long-Sleeve Shirt - Women's
    $69.97
    Save 30%
    compared to  $100.00
    434 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    REI OUTLET
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Men's
    $125.00
    1115 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    Top Rated
    SmartwoolClassic Thermal Merino Crew Base Layer Top - Women's
    $79.97 - $86.97
    Save 30%
    compared to  $115.00 - $125.00
    1557 reviews with an average rating of 4.8 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
    Top Rated
    SmartwoolClassic Thermal Merino Base Layer Quarter-Zip - Men's
    $89.73
    Save 25%
    compared to  $120.00
    71 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 Crew Top - Kids'
    $34.95
    9 reviews with an average rating of 4.9 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    tasc PerformanceElevation Merino T-Shirt - Women's
    $54.73
    Save 30%
    compared to  $79.00
    98 reviews with an average rating of 4.4 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    REI OUTLET
    Top Rated
    REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Men's
    $44.95
    52 reviews with an average rating of 4.5 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    REI Co-opMidweight Long-Sleeve Crew Base Layer Top - Women's
    $64.95
    7 reviews with an average rating of 4.1 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    Top Rated
    SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Men's
    $100.00
    545 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Top Rated
    SmartwoolClassic Thermal Merino Quarter-Zip Base Layer Top - Women's
    $89.93 - $130.00
    1090 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    SmartwoolClassic Thermal Merino Colorblock Crew Base Layer Top - Men's
    $90.87
    Save 30%
    compared to  $130.00
    2 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 Crew Base Layer Top - Men's
    $86.97
    Save 30%
    compared to  $125.00
    334 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    REI OUTLET
  • A yellow Member Bonus Card and two holiday-themed gift cards on a light colored background.

    Give the gift of the outdoors

    Members, get a $25 bonus e-card when you buy a $130+ gift card. Terms apply.

    Shop gift cards
    Top Rated
    REI Co-opLightweight Base Layer Crew Top - Kids'
    $22.43
    Save 25%
    compared to  $29.95
    14 reviews with an average rating of 4.9 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular
    REI Co-opMerino 250 Half-Zip Base Layer Top - Men's
    $109.95
    1 reviews with an average rating of 5.0 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Big, Tall
    Hot ChillysOriginals Solid Base Layer Crew - Kids'
    $34.73
    Save 29%
    compared to  $49.00
    0 reviews
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
    PatagoniaCapilene Lightweight Crew Base Layer Top - Men's
    $75.00
    0 reviews
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Big
    Top Rated
    IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Women's
    $120.00
    96 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    Top Rated
    REI Co-opMidweight Long-Sleeve Crew Base Layer Top - Men's
    $64.95
    8 reviews with an average rating of 4.6 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big, Tall
    REI Co-opMerino 185 Long-Sleeve Crew Base Layer Top - Women's
    $84.95
    4 reviews with an average rating of 3.8 out of 5 stars
    Underwear Weight:
    Lightweight
    Size Type:
    Regular, Plus
    ObermeyerComfy Cozy Base Layer Set - Kids'
    $31.67
    Save 46%
    compared to  $59.00
    1 reviews with an average rating of 1.0 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular
    REI OUTLET
    SmartwoolIntraknit Thermal Merino Crew Base Layer Top - Women's
    $96.73
    Save 25%
    compared to  $130.00
    239 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
    $150.00
    239 reviews with an average rating of 4.3 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular
    SmartwoolIntraknit Thermal Max Merino Quarter-Zip Base Layer Top - Women's
    $107.87
    Save 30%
    compared to  $155.00
    30 reviews with an average rating of 4.3 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular
    REI OUTLET
    Top Rated
    REI Co-opMidweight Half-Zip Base Layer Top - Women's
    $69.95
    10 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Plus
    PatagoniaCapilene Midweight Crew Base Layer Top - Men's
    $95.00
    0 reviews
    Underwear Weight:
    Midweight
    Size Type:
    Regular, Big
    Top Rated
    Icebreaker260 Tech Long-Sleeve Crewe Base Layer Top - Women's
    $140.00
    71 reviews with an average rating of 4.7 out of 5 stars
    Underwear Weight:
    Heavyweight
    Size Type:
    Regular, Plus
Sort: Best Match

Related Expert Advice articles

Illustration of a hand holding a phone.

Checkout faster

Track your order, shop and save— all in one place

Get the REI app