Long Sleeve Base Layer Tops
(195 products)- REI Co-opMidweight Long-Sleeve Base Layer Top - Men'sTop Rated$37.93 - $54.95Underwear Weight:MidweightSize Type:Regular, Big, Tall
- REI Co-opMidweight Base Layer Half-Zip Top - Men'sTop Rated$41.93 - $59.95Underwear Weight:MidweightSize Type:Regular, Big, Tall
- REI Co-opMidweight Long-Sleeve Base Layer Top - Women's$54.95Underwear Weight:MidweightSize Type:Regular, Plus
- IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Men'sTop Rated$69.93 - $120.00Underwear Weight:MidweightSize Type:Regular, Big
- SmartwoolClassic Thermal Merino Crew Base Layer Top - Women'sTop Rated$125.00Underwear Weight:MidweightSize Type:Regular, Plus
- REI Co-opMidweight Base Layer Half-Zip Top - Women's$59.95Underwear Weight:MidweightSize Type:Regular, Plus
- REI Co-opHeavyweight Merino Long-Sleeve Base Layer Crew Top - Women's$69.93 - $99.95Underwear Weight:HeavyweightSize Type:Regular, Plus
- REI Co-opHeavyweight Merino Long-Sleeve Base Layer Crew Top - Men's$69.93 - $99.95Underwear Weight:HeavyweightSize Type:Regular, Big, Tall
- REI Co-opHeavyweight Merino Base Layer Half-Zip Top - Women'sTop Rated$72.93 - $104.95Underwear Weight:HeavyweightSize Type:Regular, Plus
- SmartwoolClassic Thermal Merino Crew Base Layer Top - Men'sTop Rated$125.00Underwear Weight:MidweightSize Type:Regular, Big
- PatagoniaCapilene Midweight Crew Base Layer Top - Men'sTop Rated$61.93 - $89.00Underwear Weight:MidweightSize Type:Regular, Big
- Arms of Andes160 Ultralight Alpaca Wool Long-Sleeve Base Layer Shirt - Men's$66.93Save 25%compared to  $90.00Underwear Weight:UltralightweightSize Type:Regular, Big
- REI Co-opMerino 185 Long-Sleeve Half-Zip Base Layer Top - Men'sTop Rated$62.93 - $89.95Underwear Weight:LightweightSize Type:Regular, Big
- IcebreakerMerino 260 Tech Long-Sleeve Crewe Thermal Top - Men'sTop Rated$89.93 - $125.00Underwear Weight:HeavyweightSize Type:Regular, Big
- IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Women'sTop Rated$69.93 - $120.00Underwear Weight:MidweightSize Type:Regular, Plus
- Arc'teryxRho LT Crew Neck Base Layer Top - Men'sTop Rated$100.00Underwear Weight:LightweightSize Type:Regular, Big
- Kari TraaRose Half-Zip Base Layer Top - Women's$97.93 - $140.00Underwear Weight:MidweightSize Type:Plus, Regular
- tasc PerformanceElevation Merino T-Shirt - Men's$34.73 - $54.73Save 30% - 56%compared to  $79.00Underwear Weight:LightweightSize Type:Regular, BigREI OUTLET
- PatagoniaCapilene Midweight Crew Base Layer Top - Women'sTop Rated$61.93 - $89.00Underwear Weight:MidweightSize Type:Regular, Plus
- tasc PerformanceElevation Merino T-Shirt - Women's$54.73Save 30%compared to  $79.00Underwear Weight:LightweightSize Type:Regular, PlusREI OUTLET
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.
Apply now- SmartwoolClassic Thermal Merino Quarter-Zip Base Layer Top - Women'sTop Rated$130.00Underwear Weight:MidweightSize Type:Regular, Plus
- Helly HansenHH Durawool Crew Long-Sleeve Shirt - Women's$64.73Save 28%compared to  $90.00Underwear Weight:LightweightSize Type:RegularREI OUTLET
- PatagoniaCapilene Midweight Zip-Neck Base Layer Top - Men's$68.93 - $99.00Underwear Weight:MidweightSize Type:Regular, Big
- REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Men's$44.95Underwear Weight:LightweightSize Type:Regular, Big, Tall
- REI Co-opMerino 185 Long-Sleeve Base Layer Top - Men'sTop Rated$79.95Underwear Weight:LightweightSize Type:Regular, Big
- Kari TraaFryd Base Layer Top - Women's$44.93 - $60.00Underwear Weight:MidweightSize Type:Regular
- REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Women'sTop Rated$44.95Underwear Weight:LightweightSize Type:Regular, Plus
- StioBasis PeakWool Midweight Half-Zip Base Layer Top - Men'sTop Rated$110.93Save 30%compared to  $159.00Underwear Weight:MidweightSize Type:Regular, Big
- SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Men'sTop Rated$66.93 - $100.00Underwear Weight:LightweightSize Type:Regular, Big
- SmartwoolClassic Thermal Merino Quarter-Zip Base Layer Top - Men'sTop Rated$130.00Underwear Weight:MidweightSize Type:Regular, Big





































































































































































