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  • Soft fabric blend of polyester and spandex breathes well, moves moisture away from skin and dries quickly
  • Fabric also offers 4-way stretch; flat seam construction prevents chafing
  • Elastic waistband with a brushed inner face fits comfortably
  • The men's REI Boxer Briefs have a classic fit and a functional fly

Made in USA.

View all REI Co-op Men's Briefs

REI membership


Best Use Hiking, Multisport
Fabric 92% polyester/8% spandex
Moisture Wicking Yes
Quick Drying Yes
Inseam (in.) 5 inches
Gender Men's

Size chart

Sizing notes

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.

Rated 1 out of 5 by from Cause Chaffing I bought a couple of pairs of these boxers to replace my older REI Boxer briefs that were discontinued. First off, why mess up a good thing? The original REI Boxer briefs were great. Very similar to Patagonia's version but more affordable. These have hems sewn into the fabric that will cause chaffing while exercising or just wearing all day long. I sweat more that average but that is why I wear expensive briefs. Not impressed with the functionality of these at all. I wish REI would bring back the original Boxer Briefs
Date published: 2015-06-08
Rated 5 out of 5 by from Possible Holy Grail of Men's Undies I am ALWAYS trying to find the Holy Grail of underwear. I like boxer brief/trunk type with very thin, light and slightly stretchy synthetic material. I really like the other REI boxer briefs that sell for $19.50, but this material is thinner, so much so that I can barely tell I'm wearing underwear at all. They seem to run about a half size large, so you may consider that when ordering. The 5" inseam is perfect. I will be ordering several more pairs of these. Thanks for another fantastic product REI.
Date published: 2014-03-16
Rated 5 out of 5 by from Best REI Underwear These boxer briefs have a very soft stretch material that is super comfortable and lightweight. The seams are flat and not noticeable. The length is perfect and they stay put without riding up. Great job REI at making some awesome boxer briefs!
Date published: 2014-04-06
Rated 5 out of 5 by from Best underwear for hiking! I have LOTS of underwear. I just used 2 pairs of these on the JMT and they were awesome. I sweat a lot and I had zero problems with these and they doubled as swim trunks. Never ride up. These are my go to from now on.
Date published: 2014-10-11
Rated 5 out of 5 by from Very comfortable I live in Daphne Al and it is very hot and humid here. These briefs work very well even on the hottest days. Purchased 4 pairs about a month ago and have been wearing them ever since they arrived.
Date published: 2014-07-24
Rated 5 out of 5 by from Good to go Very similar to Exofficio, maybe a better fit overall. I bought the REI version because they were out of my size. I'm impressed.
Date published: 2014-07-04
Rated 4 out of 5 by from Solid undies I purchased these and some ExOfficio Give-n-go boxer briefs at the same time. Overall I prefer the give-n-gos, but these are still a solid choice. They feel great and do wick moisture well. The difference is that these don't necessarily "feel" like they are wicking moisture until you reach down and check ;) They are pretty clingy which is fine until I start to sweat. They slide down and have to be pulled up every now and then. Overall I'm happy with them.
Date published: 2016-04-03
Rated 5 out of 5 by from Never felt they were there I sweat a lot, and these performed incredibly. Never felt they were there.
Date published: 2014-08-18
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how much do they weigh (the large size)

Asked by: DasWulf
​Size large weighs 3 ounces.
Answered by: REIservice
Date published: 2017-02-05

Any chance you guys are going to add a few more color options? I'd like to purchase another set or two but would like to have them in another color.

Asked by: lwob85
​As of September 2016, we will not be getting any new colors for the near future.
Answered by: REIservice
Date published: 2016-12-19

What is the best way to wash these?

Asked by: jmarkowi
We recommend washing the briefs in cold water on the gentle cycle. Use a mild detergent and do not use any bleach or fabric softeners. They can be tumble dried on low heat.
Answered by: REIservice
Date published: 2016-08-15
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