Base Layer Tops
(220 products)- REI Co-opMidweight Long-Sleeve Base Layer Top - Men'sTop Rated$37.93 - $54.95Underwear Weight:MidweightSize Type:Regular, Big, Tall
- REI Co-opHeavyweight Merino Long-Sleeve Base Layer Crew Top - Men's$69.93 - $99.95Underwear Weight:HeavyweightSize 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-opHeavyweight Merino Long-Sleeve Base Layer Crew Top - Women's$69.93 - $99.95Underwear Weight:HeavyweightSize Type:Regular, Plus
- SmartwoolClassic Thermal Merino Crew Base Layer Top - Men'sTop Rated$125.00Underwear Weight:MidweightSize Type:Regular, Big
- REI Co-opMidweight Long-Sleeve Base Layer Top - Women's$54.95Underwear Weight:MidweightSize Type:Regular, Plus
- REI Co-opMidweight Base Layer Half-Zip Top - Women's$59.95Underwear Weight:MidweightSize Type:Regular, Plus
- SmartwoolClassic Thermal Merino Crew Base Layer Top - Women'sTop Rated$125.00Underwear Weight:MidweightSize Type:Regular, Plus
- REI Co-opLightweight Long-Sleeve Crew Base Layer Top - Women'sTop Rated$44.95Underwear Weight:LightweightSize Type:Regular, Plus
- SmartwoolClassic All-Season Merino Long-Sleeve Base Layer Top - Men'sTop Rated$66.93 - $100.00Underwear Weight:LightweightSize Type:Regular, Big
- REI Co-opMerino 185 Long-Sleeve Base Layer Top - Men'sTop Rated$79.95Underwear Weight:LightweightSize Type:Regular, Big
- REI Co-opLightweight Crew Base Layer Top - Men'sTop Rated$14.83 - $34.95Underwear Weight:LightweightSize Type:Regular, Big, Tall
- Arc'teryxRho LT Crew Neck Base Layer Top - Men'sTop Rated$100.00Underwear Weight:LightweightSize 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 Half-Zip Base Layer Top - Men'sTop Rated$62.93 - $89.95Underwear Weight:LightweightSize Type:Regular, Big
- REI Co-opMerino 185 Base Layer Top - Men's$69.95Underwear Weight:LightweightSize Type:Regular, Big
- REI Co-opHeavyweight Merino Base Layer Half-Zip Top - Women'sTop Rated$72.93 - $104.95Underwear Weight:HeavyweightSize Type:Regular, Plus
- IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Women'sTop Rated$69.93 - $120.00Underwear 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
- REI Co-opLightweight Half-Zip Base Layer Top - Men'sTop Rated$49.95Underwear Weight:LightweightSize Type:Regular, Big
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Terms apply- REI Co-opHeavyweight Merino Base Layer Half-Zip Top - Men's$72.93 - $104.95Underwear Weight:HeavyweightSize Type:Regular, Big, Tall
- Icebreaker200 Oasis Long-Sleeve Half-Zip Base Layer Top - Women'sTop Rated$79.93 - $130.00Underwear Weight:LightweightSize Type:Regular, Plus
- REI Co-opMerino 185 Long-Sleeve Base Layer Top - Women's$79.95Underwear Weight:LightweightSize Type:Regular
- PatagoniaCapilene Midweight Crew Base Layer Top - Women'sTop Rated$61.93 - $89.00Underwear Weight:MidweightSize Type:Regular, Plus
- Arc'teryxRho LT Base Layer Hoody - Men'sTop Rated$120.00Underwear Weight:LightweightSize Type:Regular, Big
- Sale Ends TodayFree CountryForce Grid Fleece Base Layer Top - Men'sTop Rated$21.73Save 51%compared to  $45.00Underwear Weight:LightweightSize Type:BigREI OUTLET
- SmartwoolIntraknit Thermal Merino Crew Base Layer Top - Men's$92.73Save 28%compared to  $130.00Underwear Weight:MidweightSize Type:Regular, BigREI OUTLET
- SmartwoolClassic Thermal Merino Quarter-Zip Base Layer Top - Women'sTop Rated$130.00Underwear Weight:MidweightSize Type:Regular, Plus
- PatagoniaCapilene Thermal Weight Zip-Neck Long Underwear Top - Women's$75.93 - $115.00Underwear Weight:HeavyweightSize Type:Regular
- PatagoniaCapilene Midweight Zip-Neck Base Layer Top - Men's$68.93 - $99.00Underwear Weight:MidweightSize Type:Regular, Big



























































































































































