How to Choose Base Layers
REI Co-op Lightweight Base Layer Bottoms - Men's
This product is not available. Good news: we have a newer version.
From morning's first frosty steps to midday sweat and exhilaration, the men's REI Co-op lightweight base layer bottoms wick and breathe to keep you comfortable all the way.
Shop newer version- Made of a soft, snag-resistant polyester blend that wicks sweat and dries fast to keep you warm in winter and cool as the season turns to spring
- Spandex in the fabric provides 4-way stretch for ease of movement
- Flatseam construction and low-profile waistband and crotch gusset keep you comfortable as you move
- UPF 50+ sun protection
- Fly opening
- Ankle-length inseam
- Semifitted
- Average weight: 6 oz.
- Made in a Fair Trade Certified™ factory
- 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
Imported.
View all REI Co-op Men's Base Layer Bottoms| Best Use | Multisport |
|---|---|
| Fabric | 92% polyester/8% spandex |
| Sun-Protective Fabric | Yes |
| UPF Rating | 50 |
| Moisture Wicking | Yes |
| Quick Drying | Yes |
| Fly Opening | Yes |
| Underwear Weight | Lightweight |
| Inseam (in.) | 27 inches |
| Gender | Men's |
| Sustainability | Fair Trade Certified™ factory 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.
Review this Product
Adding a review will require a valid email for verification
Most Helpful Favorable Review
Great base layer
JBCLE4 years ago
Perfect base layer for winter running in Cleveland. I’m 6’2”, 32” waist, medium fits great, although it hits above the ankle, slightly higher than pictured on model. Not a problem for me. Wear them with shorts on top and provides sufficient warmth and wind protection, especially once I get moving. Coldest I’ve worn them in is about 15 degrees, but worked just fine. Recommend.
JBCLE
Cleveland, OH
14 people found this review helpful
Most Helpful Critical Review
Inseam runs short
David27965 years ago
I just received these lightweight bottoms which seem very well made, but the stated 32” inseam (in size large) unfortunately fits like a 30” on me anyway. I will have to return them and try a pair of the tall sized bottoms.
David2796
Harrisburg, PA
12 people found this review helpful
Customer Images
Keith
Huntington Beach
Impressed and pleased with these dry-fits
1 year ago
Im a Structural Union Ironworker by profession and i need to wear garments that will keep me cool because the work i do is like being at the gym 8-10 hours a day. I wear these under my pants as my underwear and at firat i was a little skeptical if they would work but after 4 weeks of using this type of lightweight dry fits , i am really impressed with them. Afyer the second day of wearing them i went back to REI and bought 3 more pairs
Age:35–44
Weight:175–200 lbs.
Height:6'0"
Yes , I recommend this product
osidd
Maryland, USA
excellent, lightweight, washed well
10 months ago
Lightweight, non-chafing, non-itching. They ride a little short at the ankle, which is ideal because you'll be wearing socks. I wear these under shorts in mild to warm weather for hiking- keep plants from brushing my skin, decrease mosquito attacks, add a little warmth. They're warmer than bare legs but wick well enough that I don't feel much sweatier for wearing them. Another bonus is avoiding thigh chafing on long hikes without needing to use bodyglide. True to size. I've worn them for 4 hikes so far (15-20 miles) and washed them 3x, without any damage or shrinkage. Like most technical fabrics, you should always line-dry them. Exactly what I wanted. Highly recommend.
Height:5'11"
Weight:200–225 lbs.
Yes , I recommend this product
James Nabi Michael
Fort Worth TX
Kilimanjaro hiking
2 years ago
Works really well for hike to top of Kilimanjaro. Excellent and used with hiking pants and ski pants near top of mountain.
Age:55–64
Weight:150–175 lbs.
Height:5'7"
Yes , I recommend this product
Cagney
Sad day for REI
2 years ago
Horribly mis-sized. Size large lightweights were 3” shorter than size mediums in silk. Return process was a total pain in the butt. REI is better than this ridiculousness!
No, I do not recommend this product
Quin
Jackson, MI
Solid 4-season base layer choice
2 years ago
I was going back and forth between these or a similar pair by Smartwool. I've never been let down in the past by REI products, and these exceeded my expectations like all the others. Most recently worn as a base layer on a four day backpacking trip where temps dropped down to 16. They kept me plenty warm while at camp, and didn't get too terribly hot while hiking. Very comfortable, not itchy and breathable. They may have been significantly cheaper than the Smartwool, but I don't think the quality or function is sacrificed because of it.
Age:25–34
Weight:175–200 lbs.
Height:Taller than 6' 5"
Yes , I recommend this product
JBCLE
Cleveland, OH
Great base layer
4 years ago
Perfect base layer for winter running in Cleveland. I’m 6’2”, 32” waist, medium fits great, although it hits above the ankle, slightly higher than pictured on model. Not a problem for me. Wear them with shorts on top and provides sufficient warmth and wind protection, especially once I get moving. Coldest I’ve worn them in is about 15 degrees, but worked just fine. Recommend.
Age:25–34
Weight:175–200 lbs.
Height:6'2"
Yes , I recommend this product
Justin
Fort Worth, texas
Comfy
5 years ago
Was Unsure because I do t typically like tight fitting clothes. But I put these on while at camp climbing Pikes Peak, and they are not only warm, but so comfortable and natural fitting. It was 29-30 degrees that night, and I was warm and comfy in my bag.
Yes , I recommend this product
TP Boyd
Houston Texas
Hunting Trip
4 years ago
Just got back from North, North Texas. Hunted 3 days in a row and it was mid 20s early in the am, I was toasty warm, wish I bought 2 pair.
Age:55–64
Weight:225–250 lbs.
Height:6'4"
Yes , I recommend this product
DanL
Seattle
Lightweight SPF leggings?
1 year ago
Patagonia used to sell a lightweight "Capilene" brand polyester legging. I liked them because they could be used in hotter summer months during camping trips to minimize sun exposure along with the application of insect repellent to keep the bugs at bay. Today, it seems only REI has this type of lightweight garment. For sizing, I normally wear 35W-32L items, so a Large fits well. I do note that the length of this particular item is shorter and does not stretch to my ankle, seemingly about 30"L. For my use it does not matter. Construction seems good, no loose threads at first glance or after washing. Breathability and fabric quality are also quite good. It will be interesting to see how they serve as an SPF garment during warmer months (will they be airy and cool?). Keep making these.
Age:55–64
Weight:175–200 lbs.
Height:5'10"
Yes , I recommend this product
Anonybus
Not soft material
5 years ago
These are light and just warm enough for winters in Georgia, but the material is not soft. Would like to be able to sleep in these in cold weather but they, sadly, aren't comfortable enough. I find myself choosing my other bargain bin base layers over these almost every time.
No, I do not recommend this product
1 - 10 of 90 Reviews