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Long Sleeve Base Layer Tops

(234 products)

Products (234)

Sort: Best Match

REI Co-opMidweight Long-Sleeve Base Layer Top - Women's
$26.83 - $38.39
Save 30% - 51%
compared to $54.95
249 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Plus
Sale Ends Sep 1
Top Rated
REI Co-opMidweight Base Layer Half-Zip Top - Men's
$41.89
Save 30%
compared to $59.95
143 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 Long-Sleeve Base Layer Top - Men's
$26.83 - $38.39
Save 30% - 51%
compared to $54.95
156 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big, Tall
Top Rated
REI Co-opMerino 185 Long-Sleeve Half-Zip Base Layer Top - Men's
$29.83 - $89.95
102 reviews with an average rating of 4.6 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
REI Co-opMidweight Base Layer Half-Zip Top - Women's
$19.83 - $41.89
Save 30% - 66%
compared to $59.95
140 reviews with an average rating of 4.4 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Plus
Sale Ends Sep 1
Top Rated
REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Women's
$27.89
Save 30%
compared to $39.95
19 reviews with an average rating of 4.6 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Plus
Top Rated
IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Men's
$51.83 - $105.00
134 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
Sale Ends Sep 1
Top Rated
REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Men's
$27.89
Save 30%
compared to $39.95
9 reviews with an average rating of 4.7 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
$29.83 - $79.95
177 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
Top Rated
SmartwoolClassic Thermal Merino Crew Base Layer Top - Women's
$81.73
Save 28%
compared to $115.00
Members use code LABORDAY2025 for an extra 20% off at REI Outlet
367 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Plus
REI OUTLET
SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Women's
$44.83 - $90.00
121 reviews with an average rating of 4.4 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Plus
Sale Ends Sep 1
REI Co-opLightweight Half-Zip Base Layer Top - Women's
$31.39
Save 30%
compared to $44.95
1 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Plus
Top Rated
SmartwoolClassic Thermal Merino Crew Base Layer Top - Women's
$115.00
1149 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Plus
Top Rated
SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Men's
$44.83 - $90.00
66 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
Kari TraaRose Half-Zip Base Layer Top - Women's
$59.83 - $140.00
30 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Plus
Sale Ends Sep 1
Top Rated
REI Co-opLightweight Crew Base Layer Top - Infants'/Toddlers'
$13.89
Save 30%
compared to $19.95
10 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
Top Rated
Arc'teryxIonia Merino Wool Base Layer Hoody - Men's
$98.93
Save 29%
compared to $140.00
50 reviews with an average rating of 4.8 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
Top Rated
REI Co-opMidweight Base Layer Crew Top - Kids'
$23.93 - $34.95
5 reviews with an average rating of 5.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
Top Rated
REI Co-opMerino 185 Long-Sleeve Half-Zip Base Layer Top - Women's
$39.83 - $89.95
102 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
tasc PerformanceElevation Merino T-Shirt - Men's
$49.73
Save 37%
compared to $79.00
Members use code LABORDAY2025 for an extra 20% off at REI Outlet
38 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big
REI OUTLET
Top Rated
SmartwoolClassic Thermal Merino Crew Base Layer Top - Men's
$115.00
1506 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
Sale Ends Sep 1
Top Rated
REI Co-opLightweight Half-Zip Base Layer Top - Men's
$31.39
Save 30%
compared to $44.95
5 reviews with an average rating of 4.8 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Big, Tall
Top Rated
IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Women's
$49.83 - $105.00
135 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Plus
SmartwoolClassic Thermal Merino Base Layer Quarter-Zip - Women's
$89.73
Save 25%
compared to $120.00
Members use code LABORDAY2025 for an extra 20% off at REI Outlet
0 reviews
Underwear Weight:
Midweight
Size Type:
Regular, Plus
REI OUTLET
Kari TraaEmbla Wool Long-Sleeve Base Layer Top - Women's
$39.83 - $90.00
0 reviews
Underwear Weight:
Ultralightweight
Size Type:
Regular
Ortovox185 Merino Rock'n'wool Long-Sleeve Base Layer Top - Men's
$54.83
Save 50%
compared to $110.00
10 reviews with an average rating of 4.2 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
REI Co-opMerino 185 Long-Sleeve Base Layer Top - Women's
$79.95
199 reviews with an average rating of 4.4 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular
Kari TraaFryd Base Layer Top - Women's
$29.83 - $65.00
21 reviews with an average rating of 4.0 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular
Top Rated
PatagoniaCapilene Midweight Crew Base Layer Top - Men's
$59.93 - $89.00
79 reviews with an average rating of 4.5 out of 5 stars
Underwear Weight:
Midweight
Size Type:
Regular, Big
Top Rated
Arc'teryxRho Zip-Neck Base Layer Top - Women's
$79.93 - $120.00
11 reviews with an average rating of 4.7 out of 5 stars
Underwear Weight:
Lightweight
Size Type:
Regular, Plus

1–30 of 234 products

Sort: Best Match

Related Expert Advice articles

What material is best?

Wool is moisture-wicking and odor-resistant, while synthetic fabrics are more durable and less expensive.

Match the temp to the trek

Lightweight layers are best for moderate to cool temperatures. Midweight layers are best for cold temperatures. Heavyweight layers are best for below-freezing temperatures.

Find your fit

To be able to wick sweat efficiently, your next-to-skin layer needs to actually be next to your skin. A comfortably snug fit everywhere is your goal.

Read full article: How to Choose Base Layers

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