Make your tot's base layer the warm, breathable, toddlers' REI Co-op Midweight Crew long underwear top and they'll play happily outside all day. It's great on its own for inside play, too.

Underwear TopsBase Layer Tops

The kids' REI Co-op Midweight Long Underwear Bottoms are warm and very good at wicking moisture, making them an ideal base layer for highly aerobic cold-weather fun, like skiing and snowshoeing.

Underwear BottomsBase Layer Bottoms

The toddlers' REI Co-op Midweight Long Underwear Bottoms are warm and very good at wicking moisture, making them an ideal base layer for highly aerobic cold-weather fun, like skiing and snowshoeing.

Underwear BottomsBase Layer Bottoms

Warm and wicking to keep you comfortable on the slopes, the men's REI Co-op Midweight Long-Sleeve Base Layer has a smooth face to easy layering and a brushed back for warmth against the cold.

Underwear TopsBase Layer Tops

Wherever you're out in the cold, you'll love the streamlined warmth, moisture-wicking comfort and easy layering of the women's REI Co-op Midweight long-sleeve base layer top.

Underwear TopsBase Layer Tops

Shred to your heart's content with the comfort of these men's Midweight X base layer bottoms. They're your quiver-of-one, serving up quick-drying, stink-free warmth for long days on the mountain.

Underwear BottomsBase Layer Bottoms

Begin your layering system with a flexible base that moves with you. The men's Burton Midweight X Base Layer Crew top also breathes with your body heat and helps control odors.

Underwear TopsBase Layer Tops

Begin your layering system with a flexible base that moves with you. The women's Burton Midweight X Base Layer Crew top also breathes with your body heat and helps control odors.

Underwear TopsBase Layer Tops

Pull up the hood, deploy the face mask and ride into the weather. The women's Burton Midweight X Base Layer Long Neck hoodie keeps you comfy with a built-in neck warmer and breathable fabric.

Underwear TopsBase Layer Tops

Pull up the hood, deploy the face mask and ride into the weather. The men's Burton Midweight X base layer long-neck hoodie keeps you comfy with a built-in neck warmer and breathable fabric.

Underwear TopsBase Layer Tops

Hit the lifts with all you've got. The women's Burton Midweight X base layer pants move right along with you with breathable, quick-drying fabric—plus, a media port stashes your phone for easy access.

Underwear BottomsBase Layer Bottoms

A go-to for your daily commute or laps on local trails, the men's PEARL iZUMi Minimal liner shorts are perfect for rides that call for just a bit of cushion—without the bulk of standard bike shorts.

UnderwearCycling Underwear Bottoms

Worn under skirts or shorts, the women's Terry Mixie liner shorts instantly transform streetwear into cyclewear. The Urban Chamois keeps you comfortable while a 6 in. inseam keeps you covered.

UnderwearCycling Underwear Bottoms

Sleek, smooth and comfortable, the women's ExOfficio Modern Collection hipster underwear offers dynamic technical performance for all your travels, both near and far.

UnderwearUnderwear Bottoms