REI Co-op Merino Bikini Underwear - Women's
Stay comfortable on the trail in this naturally breathable and odor-resistant REI Co-op Merino Bikini Underwear. It's durable and soft for an all-day hike or just lounging at camp.
- Bikini has a higher rise and slightly more coverage in back compared to our Hipster underwear
- Ultrafine 150 g (17.5-micron) core-spun nylon is wrapped in merino wool and blended with TENCEL™ to offer the ultimate combination of durability and next-to-skin softness
- Merino wool regulates body temperature, manages sweat, dries quickly, naturally resists odor and has 4-way stretch for ease of movement
- Pill- and snag-resistant for durability
- Soft elastic waistband and trim leg openings hold underwear in place during movement
- Side seams shifted forward to maximize comfort
- Machine wash warm, wash with like colors, on gentle cycle; use wool wash product; do not twist or wring; remove promptly; do not bleach; tumble dry low
- 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 Women's Briefs| Best Use | Multisport |
|---|---|
| Underwear Style | Bikini |
| Fabric | 49% merino wool/30% TENCEL lyocell/15% nylon/6% LYCRA spandex |
| Moisture Wicking | Yes |
| Quick Drying | Yes |
| Gender | Women's |
| Sustainability | Fair Trade Certified™ Factory From a Climate Label Certified brand |
Fits slightly large based on reviews
| XXS | XS | S | M | L | XL | 1X | 2X | 3X | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18W | 20W | 22W | 24W | 26W | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Numerical Size | 00 | 0-2 | 4-6 | 8-10 | 12-14 | 16 | 18 | 20-22 | 24-26 | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 | 26 |
| Bust | 31 | 32-33 | 34-35 | 36-37 | 38.5-40 | 41-42.5 | 43-45 | 47-49 | 51-53 | 32 | 33 | 34 | 35 | 36 | 37 | 38.5 | 40 | 42.5 | 45 | 47 | 49 | 51 | 53 |
| Sleeve Length | 29.5 | 30 | 30.5 | 31 | 31.5 | 32 | 32.5 | 33.5 | 34.5 | 30 | 30 | 30.5 | 30.5 | 31 | 31 | 31.5 | 31.5 | 32 | 32.5 | 33.5 | 33.5 | 34.5 | 34.5 |
| Waist | 24.5 | 25.5-26.5 | 27.5-28.5 | 29.5-30.5 | 32-33.5 | 34.5-36.5 | 37.5-39.5 | 40.5-42.5 | 44.5-46.5 | 25.5 | 26.5 | 27.5 | 28.5 | 29.5 | 30.5 | 32 | 33.5 | 36 | 38.5 | 40.5 | 42.5 | 44.5 | 46.5 |
| Hip | 34 | 35-36 | 37-38 | 39-40 | 41.5-43 | 44-46 | 47-49 | 50-52 | 54-56 | 35 | 36 | 37 | 38 | 39 | 40 | 41.5 | 43 | 45.5 | 48 | 50 | 52 | 54 | 56 |
| Inseam | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 |
Sizing Notes
Measurements are stated in inches unless otherwise indicated. Size chart values represent body measurements, not garment measurements. Some women's pants are available in petite and tall sizes. Typically petite sizes fit women 4'11" to 5'3". Regular sizes fit women 5'4" to 5'8". Tall sizes fit women 5'9" to 5'11".
PETITE: Generally, as compared to regular sizes, petite sizes are 2.5 inches shorter in inseam, 1 inch shorter in body length, 1.25 inches shorter in sleeve length and ¾ inch shorter in total rise.
TALL: tall sizes are 3 inches longer in inseam, 2 inches longer in body length, 2.5 inches longer in sleeve length and 1.25 inches longer in total rise.
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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Most Helpful Critical Review
I love a merino granny panty
After checking out reviews, I was a little hesitant to purchase these, but I'm glad that I did. Ladies, these are a full coverage panty and there's nothing wrong with that! I did purchase these to wear around the house, under sweatpants, and during nights while camping, and they keep me warm, dry, and are super comfy. Yes, they have a high rise in the back but I wouldn't say they run "large," that is just the cut. Obviously you will wear thongs during the day if you're worried about panty lines. Get these if you want a high quality granny panty, wear high-waisted and looser-fit pants, and want to embrace your comfy, middle-aged identity.
Product looks great, but is way too big!
I ordered a medium as I always purchase the REI Co-op Active Bikini Underwear in a medium and they fit great. (Unfortunately, they have been hard to find in my size lately.) I ordered these online and when I compared the size difference to my Co-op underwear, these were like granny-panties and were huge. I didn't even need to try them on. They are going back. Positive note: The material feels nice and soft and I like the elastic material on the waistband. I might try them in an extra small.
Almost Perfect
I love the soft fabric of this bikini. I really like the colors. I got the sea forest. Fits true to size. I thought the coverage was too much for a bikini, more like a boy short. The bikini kept me feeling dry on a sunny hike. This bikini comes up too high for my liking and comfort. I'm not used to such a fit, and it didn't feel too good with the elastic at the mid-tummy. Due to that, I'm constantly aware that I am wearing it. It's definitely not the one I reach for - for hours of adventure. Less fabric, no-show seams, and a little shorter and you have your perfect bikini!
Great for active adventures
The only issue I had with these underwear was the size was not close to what I am used to. I wear a solid size medium in just about anything sized by S, M, L, ... However, these were really big, especially in the back end. They fit fine around the waist and legs, but there was too much material in the back so they seemed to bag and get loose when I was sweating. They were otherwise comfortable, dryed quickly on the trail and there was no issues with odor at all. They fit more like a hipster than a bikini, but I liked the wide waistband and two tone design. If they were a better fit, they would be perfect.
Wish these were seamless
Pros: * Extremely comfortable * Full coverage * No movement, bunching or chafing during activities Cons: * Thick seams are very visible through pants * Waistband comes up higher than my pants Would love to see a seamless version of these. They were great for lounging at home, but too visible for wearing out in public.
Finally we get some plus size merino undies!
Great undies, soft and stretchy. Seem well made, all seams look good. And I love merino - antimicrobial for the win! The only complaint I have is these give me wedgies. all. the. time. I think the butt cheeks need another inch or two of fabric to each side. I got a wide load coming though. That being said, I'll still wear them. I just have to be aware where I'm going that day, because I will be picking my seat.
Comfortable, Soft, Cute
I splurged and bought one pair of these because I was really curious about merino as an underwear fabric, and they're so great. if they weren't so expensive, I'd buy them for all of my daily wear. They're odor resistant, comfortable, and come in cute colors. I'm usually an XL or 2X and I bought a 3X and they fit great. You know underwear is great when you don't think about it at all, and that's this.
Great for Activities
I bought these just before my husband and I took a paddling trip to the Allagash Wilderness Waterway in Maine at the end of Sept. They dried fast and kept me warm when they got wet. Remained comfortable even after we went hiking for the day. I think the fit is perfect for activities and I really like the comfort of the waist band & the coverage, they felt secure and I did not have to keep making adjustments. So glad I had these for the trip, and when I used other underwear they did not dry as quickly as these. Washed and dried well in the backcountry. I really like them, I just ordered 2 more in 2 different colors.
Inca Trail tested! Outstanding wicking undies
I find most synthetic “wicking” underwear to be nonwicking and generally uncomfortable. These wool blend undies are just fabulous. Super soft, stay in place, truly wicking, and not stinky after a day on the trail. They dry fast too so they are great for camping. I liked them so much that I bought the matching bras. Highly recommend! (The “bikini” looks huge and like a brief, but it’s the right shape to stay in place.)
Super Comfortable while moving with your body
These REI Co-Op underwear are a must have for any person with movement in their life. The underwear had great support and light shaping but didn't pinch, bunch or chafe. They moved with my body and allowed for wicking and comfort. I never overheated or felt damp. Sizing felt true to fit and the item didn't shrink when using machine wash & dry cold cycle.