Seamless Merino Wool Base Layers for Women
BRANWYN’s seamless Merino wool bras, underwear, and leggings are an essential base layer for women heading out on cold weather adventures. Merino wool absorbs moisture without feeling wet, helping you stay warm and dry from the first layer out. Our seamless designs fit like a second skin, so you can layer up without feeling bulky or constricted. Whether you’re skiing, hiking, ice skating, or just trying to stay warm this winter, BRANWYN keeps you toasty when it’s cold, cool when it’s hot, and dry when you break a sweat.
Seamless Merino Wool Leggings
Seamless Merino Wool Bras
Seamless Merino Wool Underwear
The Best Cold Weather Leggings
"These are easily among the best leggings for hiking in cooler seasons–their merino wool hiking leggings hit that perfect balance of flattering, compressive, and warmth. The thicker fabric keeps you cozy on chilly mornings without feeling bulky, and the seamless design gives them a sleek, sculpted fit that holds everything in place. Plus, they resist odor even after multiple wears".
- Follow Tiff’s Journey, "Best Hiking Leggings for 2026"
Great fit and comfort
⭐⭐⭐⭐⭐
"As an avid outdoor enthusiast, hiker and ski instructor, I need something that doesn’t make me cold if I sweat. I tried the Branwyn busty bra and it stays put, has great coverage for the girls, smooth fit without seams, and with the straps crisscrossed in back, no strap movement off my shoulders. It stays warm and dry under my base layers. I was so happy I bought a second one in another color."
- Cynthia M.
FAQ
A base layer is the first layer of clothing you put on, worn directly against your skin. Its main job is to move sweat away from your body because damp skin loses heat fast, even under a warm jacket.
If your base layer holds moisture, no amount of insulation on top will keep you comfortable, which is why the fabric you choose here matters more than any other layer.
Your bra and underwear are the original base layer because they are the first layers against your skin and the foundation of your entire layering system. Even if you are wearing Merino wool thermal layers, if your underwear is not moisture-wicking, it can leave you feeling damp and uncomfortable when sweat builds up.
Merino wool base layers naturally regulate temperature, wick moisture, and resist odors, helping you stay comfortable through changing conditions. Unlike many synthetic base layers, Merino wool is a natural, renewable fiber that absorbs moisture vapor while staying breathable and comfortable against your skin, keeping you warm and dry.
Yes, Merino wool's crimped texture naturally insulates by trapping warmth in small air pockets, so you can stay warm without wearing something thick and bulky. It also keeps insulating when it gets damp from sweat, unlike cotton, which holds moisture against your skin and leaves you chilled. These attributes make Merino wool a great choice for active days where you’ll warm up and cool down.
Start with merino wool underwear and a thin, fitted merino base layer, which can hold up to 30% of its weight in moisture without feeling wet while wicking sweat away, so you stay dry and warm. Add a mid-layer chosen for how well it traps heat rather than how thick it is, since a thin half-zip often does the job of a bulky sweater. Finish with a lightweight shell that blocks wind and rain, and make sure each layer fits well enough to move freely without bunching. For more tips, check out our blog on layering for cold weather.