REI Co-op Merino Boxer Briefs - Men's
Stay dry on the trail in the soft, breathable and naturally odor-resistant REI Co-op Merino Boxer Brief underwear for men. They're made to keep you comfy throughout the day.
- Ultrafine 150 g core-spun nylon is wrapped in merino, offering a soft feel without any itchiness
- Merino wool naturally breathes, wicks away sweat, dries quickly and resists odors, making it an ideal multiday trip companion
- Flat seams and merrow stitch construction eliminate chafing
- Soft elastic waistband keeps underwear in place
- Shaped, functional fly
- Machine wash warm; tumble dry low
- Designed to hug the body for optimum performance
- 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 Boxers| Best Use | Multisport |
|---|---|
| Underwear Style | Boxer Brief |
| Fabric | 48% merino wool/32% TENCEL lyocell/15% nylon/5% LYCRA spandex |
| Moisture Wicking | Yes |
| Quick Drying | Yes |
| Fly Opening | Yes |
| Inseam (in.) | 6 inches |
| Gender | Men's |
| Sustainability | Fair Trade Certified™ factory From a Climate Label Certified brand |
| 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.
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.
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Awesome fit and color
Love the golden olive color. Fabric feels luxurious. I use the 100% merino boxers from Houdini Sportswear and these are not drastically different in terms of look and feel, but I do have a preference for the Houdinis, even if I prefer the colors of the REIs. In terms of fit, like they were tailored. I bought several mediums hoping the reviews would not apply to my case and I was right. I’m 5’11” 178lbs, wear pant waist 33” or 34” depending on the brand of pants, and the medium boxers fit great. The legs are also spot on in terms of fit. Above all, feel great that the wool is allegedly mulesing-free and made in a fair-trade factory. I’ll have to take REIs word on that. Wish there was a way to trace the wool, like how some down products are source traceable.
Fantastic until they fall apart
I got these for my partner who loved them instantly, so we got several more pairs over the next few months. The first pair, ordered Nov 2023, are now disintegrating between the thighs 8 months later. Despite this, he says they're the most comfortable underwear he's ever owned and they stay feeling fresh for a while between washes. They're worth it if you get them on sale but I wouldn't spend $40 per pair in the future.
1 fatal flaw, printed tag breaks apart and itches
Almost perfect but the printed tag eventually breaks down and itched your back in a most irksome way. Otherwise great
Elastic wears out faster than other merino brands
I love merino underwear and wear it all 4 seasons. My normal brand is Icebreaker, and each pair in my rotation has lasted about 2 years before the wool wears out. Tempted by the lower price tag, I added one pair of REI into the rotation 4 months ago but the waistband has already started losing elasticity after a couple months. So even with a higher initial price, the Icebreaker gets more lifetime per dollar.
no bunch comfortable all day
I have a 35” waist. I purchased medium which were just a tad bigger than I’d like, decided to wash warm and dry on low (as per instructions) they fit perfect after! I have a pair of smartwool and icebreakers these are better in every way. Nice thick waistband but unlike SW they don’t fold in on themselves. Leg length is longer than both SW and IB but not so long they show with athletic shorts. The fly is actually functional unlike IB which is way to small and SW fly is just a little to small! All in all they are great and hope with proper care they will hold up!
All Good !!
Reviewed these when I first received them several months ago. At the time, I was not sure how they would wear. (I wear each pair maybe once a week--around town, easy hiking, etc--so, not extreme use.) That said, they are extremely comfortable. The fabric seems to have hit a sweet spot. I got some of the same style in all nylon at the same time, thinking they might be better for hot weather. Wrong !! These are definitely preferred every day--even now, when it is definitely hot. Style depends upon the individual. For me, These are a clear winner !! (So much so that I decided to leave this second, updated review.) Now I just have to hope they do not "improve" them into something less suitable for me.. :)
Comfy but 1 gripe
Trying to transition all of my underwear to wool and these were more affordable than Smartwool and ice breaker. Very comfortable and don't retain odor. My only gripe is the legs are really loose compared to the other brands causing some bunching while biking and running. They are pretty comfy for non athletic wear so I kept one pair and returned the others
Perfect very base base layer
I like Merino wool base layers for extended backpacking or strenuous activities because they do not retain odor and don't leave that odd feeling on my skin after an extended wear like some synthetics. I tried the REI brand finally and the fit is the best of what I've tried. That SW brand was to tight at the same sizing. Like so much I purchased two more pair while they were on sale.
Very good quality, run large
I've had these now for about two months and worn them a few times. First thing I noticed when opening the package is the size. They're a good 2 inches larger than any other medium brief I own. Tried to shrink them by drying in the dryer after the first wash but they retained their size. For me, they're a little more loose fitting than I like but if you're on the small size of medium, they may be too large. Quality - really nice. A very good blend of materials that wear well, wick well and appear to have longevity. They are a majority merino - an absolutely incredible material - but have some man-made fibers as well. Which, for underwear, makes lots of sense. Merino would not hold up well as underwear unless it were an uncomfortably heavy fabric. These would be great under a base layer as they are relatively thin, lighter than a cotton.
Good for everyday use
I was excited to try out these boxer briefs. I typically use wool tops for backpacking and travel, but the 100% wool underwear I have tried in the past worn out too quickly. As these use a mix of core-spun nylon wrapped in wool and lyocell, I haven’t seen any wear issues even after many washings. The fabric is silky smooth, itch free, breathes well and the wool does help with odor control. The waistband is sung without being too tight and is just the right width. On some bands the waist bands have gotten so wide and thick that they get sweaty when its hot out. The boxer-brief fits snug, but without any compression. All this makes them a great everyday pair. For active use I prefer a pair with a level of compression. I was disappointed to see that the washing instructions stated: “Do not twist or wring”. Sorry, but that is how I get the water out of clothes when backpacking and traveling. My only other issue with the Co-op merino boxer briefs is that they are a bit long in the leg and therefore they show when I’m sitting in some of my shorts. Other pluses for these boxer briefs are that they are Fair Trade Certified and use Responsible Wool Standard wool. In summary, I recommend them for everyday use (with long pants), but I’m still looking for my perfect pair of wool underwear for backpacking and travel.