You are using a web browser we don't support. Please use the latest version of one of these browsers.

Mozilla Firefox

Google Chrome

Apple Safari

Microsoft IE

Back to top

Patagonia Capilene 1 Silkweight Long Underwear Bottoms - Men's


This product is no longer available, but don't go just yet.


  • Stretchy, quick-drying and moisture wicking, the polyester and spandex fabric offers very light insulation against skin
  • Fabric provides UPF 50+ sun protection, shielding skin from harmful ultraviolet rays
  • Fabric treatment helps deter odors
  • Brushed elastic waistband won't irritate skin
  • Gusseted crotch allows freedom of movement
  • Offset seams enhance mobility without chafing; functional fly
  • The men's Patagonia Capilene 1 Silkweight Long Underwear Bottoms feature a slim fit


View all Patagonia Men's Long Underwear Bottoms

REI membership


Best Use Multisport
Fabric 94% polyester/6% spandex
Sun-protective fabric Yes
UPF Rating 50
Moisture wicking Yes
Quick drying Yes
Underwear weight Ultralightweight
Inseam (in.) 34 inches
Gender Men's

The REI Difference

100% satisfaction guaranteed

We stand behind everything we sell. If you are not satisfied with your REI purchase, you can return it for a replacement or refund within one year of purchase.

REI's guarantee doesn't cover ordinary wear and tear or damage caused by improper use or accidents.

If your item has a manufacturing defect in its materials or workmanship, you can return it at any time. See our limited warranty.

Gear & advice you can trust

At REI, we live and breathe the outdoors, and we're passionate about sharing our expertise with people of all skill levels. Whether you're new to the outdoors or a seasoned explorer, we'll take the time to understand your needs and help you find the right gear for you.

10% annual member refund

Anyone can shop at REI, but for a one-time $20 fee you can become an REI member and enjoy a lifetime of benefits. These include an annual member refund, typically 10% back on eligible purchases.*




*10% is typical but not guaranteed. Your refund is based on eligible purchases, which exclude REI gift cards, services, fees, REI Adventures trips,, and discounted items. Learn more