What Our Gearhead® Experts Are Saying: "These are my go-to baselayer bottoms when I know it’s going to be freezing. The merino is super soft, never itchy, and the temp regulation is amazing on long tours—I don’t overheat on the climb, but I stay warm on the descent. They also don’t get funky, even after multiple days of riding." We rely on the Classic Thermal Merino Baselayer Bottom when winter sends bitter cold across the mountains and we need the warmest foundation for long days outside. Smartwool’s premium merino wool keeps us insulated without feeling bulky, regulating body temperature whether we’re pushing hard on a skintrack or sitting still on a windy chairlift. Its natural breathability and softness make it a layer we forget we’re wearing—until we appreciate just how warm we feel in icy temps.Flatlock seams prevent chafing during high-output movement, and the slim fit layers smoothly under our shell pants for streamlined comfort. Thanks to merino’s natural odor resistance, these baselayers stay fresh through multi-day missions, hut trips, and back-to-back powder days alike. Cozy, functional, and built for true winter conditions, they’re a cold-weather essential.
Material: 100% merino wool;
Insulation Weight: mid;
Fit: slim;
Anti-Odor: natural attribute of merino wool;
Claimed Weight: 8.04 oz;
Activity: skiing, snowboarding, hiking, winter camping, mountaineering;
Manufacturer Warranty: 2 year;
storecredits: 0.0;
Style Variants
Available Colors: Winter Moss Heather, Deep Navy, Charcoal Heather, Black
Size Reference for SmartWool Baselayer Bottom - Men's
Available Sizes: S, M, L, XL, XXL
