Mens Underwear

When the day starts early and ends late, what's closest to your skin matters most. Men's Underwear from Smartwool is merino-first underwear built for hiking, travel, and everyday wear — soft on skin, breathable on the move, easy to wear again tomorrow. Explore our thermal underwear for cold-weather layering, or browse men's thermal trousers to complete your base layer kit. Looking to kit out the whole crew? Discover women's thermal underwear too.