How to Choose Base Layers
REI Co-op Midweight Base Layer Bottoms - Men's
This product is not available. Good news: we have a newer version.
Keep moisture out and heat in when you need it with the REI midweight base layer bottoms. They're ideal for highly aerobic cold-weather fun, such as skiing, hiking and snowshoeing.
Shop newer version- Durable polyester/spandex blend wicks moisture and dries quickly
- Mineral-based LAVA™ finish keeps fabric odor-free
- Flatseam construction and low-profile waistband and crotch gusset keep you comfortable as you move
- UPF 50 sun protection
- Fly opening
- Fitted
- Contains materials that meet the bluesign® criteria
- 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
| Best Use | Multisport |
|---|---|
| Fabric | 89% polyester/11% spandex (bluesign® approved) |
| Sun-Protective Fabric | Yes |
| UPF Rating | 50 |
| Moisture Wicking | Yes |
| Quick Drying | Yes |
| Gender | Men's |
| Sustainability | Contains materials that meet the bluesign® criteria From a Climate Label Certified brand |
REI Co-op Clothing - Men's
| XS | S | M | L | XL | XXL | XXXL | 24 IN Waist | 26 IN Waist | 28 IN Waist | 30 IN Waist | 31 IN Waist | 32 IN Waist | 33 IN Waist | 34 IN Waist | 35 IN Waist | 36 IN Waist | 38 IN Waist | 40 IN Waist | 42 IN Waist | 44 IN Waist | 46 IN Waist | 48 IN Waist | 50 IN Waist | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chest | 35 | 36 - 38 | 39 - 41 | 42 - 45 | 46 - 49 | 50 - 53 | 54 - 57 | |||||||||||||||||
| Sleeve Length | 32 | 32.5 | 33 | 33.5 | 34 | 34.75 | 35.5 | |||||||||||||||||
| Waist | 27.5 | 28 - 30 | 32 - 34 | 36 - 38 | 40 - 42 | 44 - 46 | 48 - 50 | 24 | 26 | 28 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 38 | 40 | 42 | 44 | 46 | 48 | 50 |
| Hip | 33.5 | 34.5 - 36.5 | 37.5 - 39.5 | 41 - 43 | 44 - 46.5 | 47.5 - 50.5 | 51.5 - 54.5 | 32 | 33.5 | 34.5 | 36.5 | 37 | 37.5 | 38.5 | 39.5 | 40.25 | 41 | 43 | 44 | 46.5 | 47.5 | 50.5 | 52.5 | 54.5 |
| Inseam | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 |
Sizing Notes
Measurements are stated in inches unless otherwise indicated. Size chart values represent body measurements, not garment measurements.
SHORT: Some pants are available in short sizes, which generally means an inseam that is 2.5 inches shorter than regular sizes.
TALL: Some pants, shirts, jackets and parkas are available in tall sizes, which generally means an inseam that is 3 inches longer and a rise that is 1 inch longer, a shirt or jacket body that is 2 inches longer, a parka body that is 2.5 inches longer and sleeves that are 2.5 inches longer than regular sizes.
Capri or cropped pants have an intentionally shorter inseam—reference the technical specs instead of this chart.
Inseam is measured to the floor.
Buying Advice
More expert advice
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.
Write a Review
Adding a review will require a valid email for verification
Location:North Tustin, CA, United States
8 years ago
What underwear?
Yes , I recommend this product
I'm an athletic guy and these fit snug in all the right places. The fabric wicks moisture like it's the only thing it's ever wanted to do in life. I wore these while boarding with the bros and my legs were toasty like the inside of a s'more. The fabric is smooth like Lionel Richie's Easy Like Sunday Morning. But don't get the wrong idea, the fabric still likes to party and is probably made from the same stuff Wolverine's claws are made of. They're strong. That's what I'm trying to say. Just buy them. You won't be disappointed. Unless you prefer to overpay for some other under-performing garment.
Location:Boston, MA, United States
8 years ago
Not great
No, I do not recommend this product
This layer is thin, warm, and stretchy. I tried country skiing in it and had a major problem. Every knee extension would pull the waist down. Stopped every 100 yards to pull my pants up. Finally got the process systemized...pull pants up first, then pull underwear just above the knee upwards for some slack. The more you sweat, the more pronounced the effect. I have a 35" waist, and 32" length, sort of a medium tall physique. My old Duofold underwear is saggy, baggy, thick and ugly but always functioned well.
Location:Johnstown, PA, United States
7 years ago
Great for sleeping in cold weather.
Yes , I recommend this product
I purchased these for sleeping in cold weather in my sleeping bag. I needed something heavier than my light-weight bottoms that I usually use for outdoor cold weather activities. I also wanted something lighter than fleece. Packs easy.
Location:Urbandale, IA, United States
8 years ago
Great product
Yes , I recommend this product
I purchased these last minute for a trip to Colorado, where the temperature was to drop. So they worked great as a base layer, working outside in 19 to 20 temps
Location:Austin, TX, United States
8 years ago
Fits like parachute pants
No, I do not recommend this product
Too big and baggie, the waist is tight and are the ankles, anybody like MC Hammer?
Location:New Jersey
8 years ago
Excellent for East Coast Winters
Yes , I recommend this product
Very warm, comfortable, and durable. Excellent for daily wear
Location:Las Vegas, NV, United States
7 years ago
Makes Walking Tours of Europe in Winter Comfortabl
Yes , I recommend this product
We visited some great cities in Eastern Europe from Christmas through New Years, with lots of walking tours on the schedule. These bottoms were the perfect weight and material for keeping warm and comfortable for hours in this climate at this time of year.
Location:Rochester, MN
9 years ago
Christmas present for my dad
Yes , I recommend this product
Bought this to give to my dad for Christmas. Not sure if he needs a small or medium as his waist is about 31. The small looks fairly small, but the medium looks too big. I ordered both sizes as I'm not sure which one he'll wear since he is kind of in between. The fabric seems nice. I do have the REI brand heavyweight base layer shirt for myself, and I really like it