REI Co-op  Midweight Base Layer Bottoms - Men's

$64.95
Members get an est. $6.49 in rewards

A good day outdoors starts with a good base layer. These synthetic base layer bottoms from REI Co-op provide midweight warmth for cold-weather adventures. They're soft and stretchy for easy movement.

Color: Black
please select a Size
Quantity
Select size for delivery dates

Members get an estimated $6.49 (10%) back on this item as a part of your annual .

Members get an estimated $6.49 (10%) back on this item as a part of your annual .
To buy,  sign in as an REI Co-op Member or join now.
Only thru 9/28
Earn 2x card rewards

Instead of 5%, earn 10% in card rewards† on REI purchases—even sale items—with your REI Co-op® Mastercard® Sep 18–28. Terms apply. Learn more

Features

  • Recycled polyester/spandex is peached for a supersoft next-to-skin layer—and has a smooth face so layers slide on easily
  • 220 g/m² fabric weight offers midweight warmth and wicks moisture to keep you comfortable, with spandex adding just the right amount of stretch
  • UPF 50+ sun protection
  • Soft elastic waistband has a low profile so it's comfortable under other layers
  • Fly opening
  • Crotch gusset allows full range of movement
  • Flat seams reduce chafing
  • Semifitted to hug the body for optimum performance
  • Locker loop makes it easy to hang these to dry or just keep them off the ground
  • Inseam length: 28 in.; Tall sizes: 31 in.
  • Machine wash cold; wash separately; gentle cycle; remove promptly; do not use bleach or fabric softeners; tumble dry low; low iron; do not dry clean
  • Contains bluepass certified material
  • REI Co-op brand is certified to The Climate Label; we actively fund efforts to reduce carbon emissions across our business and support climate projects around the world
  • Made in a Fair Trade Certified™ factory

Imported.

View all REI Co-op Men's Base Layer Bottoms

Technical Specs

Best Use

Multisport

Fabric

92% recycled polyester/8% spandex (bluesign® approved)

Sun-Protective Fabric

Yes

UPF Rating

50+

Moisture Wicking

Yes

Fly Opening

Yes

Underwear Weight

Midweight

Inseam (in.)

28, 31 inches

Gender

Men's

Sustainability

Contains materials that meet the bluesign® criteria

Contains recycled materials

Fair Trade Certified™ Factory

From a Climate Label Certified brand

Reviews

2 reviews with an average rating of 5.0 out of 5 stars

0% 0 of 0 reviewers recommended

Write a Review

Adding a review will require a valid email for verification

Customer Images

TravisB
Rated 5.0 out of 5 stars
2 weeks ago

Premium comfort and performence

Received free product

I recently received the REI Co-op Midweight Base Layer Bottoms in a size medium, and they have quickly become a staple in my outdoor gear lineup. Now used for multiple camping and backcountry experiences. At 5'6" with a 31-inch waist, finding the right fit can sometimes be a gamble, but the medium fits perfectly—even more so after the first wash! The waistband sits comfortably without digging in, and the length is just right—no awkward bunching at the ankles or pulling at the waist or crotch when moving around. The first thing I noticed was the incredibly soft feel against the skin. At first I thought they were part merino wool, only to learn that I’m getting the feel and warmth of wool without the high price. There is absolutely no scratchiness, making them comfortable enough to wear all day long under hiking pants, running shorts, or even as loungewear around camp—and I do like to lounge around the camp! When it comes to performance, they provide excellent warmth without causing me to overheat during active use. They insulate beautifully on those chilly mornings standing iaround the camp kitchen, while remaining breathable enough to regulate body temperature as things warm up. One subtle but highly practical design feature is the inclusion of a locker loop. It is incredibly handy for hanging them up to air out or dry overnight, whether you are using a hook in a cabin or a paracord line at a backcountry campsite. If you are looking for a reliable, comfortable, and well-designed thermal layer, these bottoms deliver.

ScottC
Rated 5.0 out of 5 stars
7 days ago

Warm and soft, perfect for sleeping in the fall or hiking in the winter.

Received free product

So far so good with these base layers! For context I live in southwest Montana where the temperature has been dipping into the mid 20s at night and have been using them as part of my sleep system for wildland firefighting. They are very soft and stretchy so they are tight fitting and don’t bunch up at all. We got a good dusting of snow one night so I decided to wear them all day as the temperatures didn’t get above 40 all day. I did get a little extra sweaty hiking in then but not too bad and the extra warmth was appreciated when we stopped to clear trail and for lunch. I would say these are perfect for low intensity activities in the fall and more moderately intense activities during the winter.

Questions & Answers

Loading Questions...
image of a girl hiking in iceland

Need help choosing gear?

Get real advice from our experts who have been there, done that.
10% co-op member reward: $6 $6 Member Reward
Your NameLIFETIME MEMBER#0123456

This purchase pays for membership!

Buy a lifetime $30 membership and make a $50 purchase by Nov 12, 2026.*

$6

10% Reward*

on this and every eligible full-price item*

+

$30

Bonus Card*

valid for 30 days after joining*

=

$36

Value

REI Co-opREI co-op logo

Better gear is built together

From feedback to field testing, all of our gear is dialed-in by REI Co-op members. Their adventures informed every stitch and detail—making for better, longer-lasting gear.

List of certifications which include The Climate Label certification,
        member informed certification and 100% satisfaction guarantee
Rei Coop brand gifREI Coop brand tent with a user inside wearing a REI Coop brand sweater
List of certifications which include The Climate Label certification,
        member informed certification and 100% satisfaction guarantee