REI Co-op  Merino Bikini Underwear - Women's

$27.95
Members get an est. $2.79 in rewards

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.

Color: Black
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Members get an estimated $2.79 (10%) back on this item as a part of your annual .

Members get an estimated $2.79 (10%) back on this item.
To buy,  sign in as an REI Co-op Member or join now.

Features

  • 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
  • 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
  • Made in a Fair Trade Certified™ factory

Imported.

View all REI Co-op Women's Briefs

Technical Specs

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

Size Chart

REI Co-op Clothing - Women's
XXSXSSMLXL1X2X3X024681012141618W20W22W24W26W
Numerical Size000-24-68-1012-14161820-2224-2602468101214161820222426
Bust3132-3334-3536-3738.5-4041-42.543-4547-4951-5332333435363738.54042.54547495153
Sleeve Length29.53030.53131.53232.533.534.5303030.530.5313131.531.53232.533.533.534.534.5
Waist24.525.5-26.527.5-28.529.5-30.532-33.534.5-36.537.5-39.540.5-42.544.5-46.525.526.527.528.529.530.53233.53638.540.542.544.546.5
Hip3435-3637-3839-4041.5-4344-4647-4950-5254-5635363738394041.54345.54850525456
Inseam3131313131313131313131313131313131313131313131

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.

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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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        member informed certification and 100% satisfaction guarantee

Reviews
52 reviews with an average rating of 4.3 out of 5 stars

79% 31 of 39 reviewers recommended

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Average Overall Fit Rating

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Most Helpful Favorable Review

18 people found this review helpful
5 reviews with an average rating of 4.0 out of 5 stars
2 years ago
Almost Perfect
Received free product
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!
Jagjas
Tampa, FL

Most Helpful Critical Review

24 people found this review helpful
5 reviews with an average rating of 3.0 out of 5 stars
2 years ago
Wish these were seamless
Received free product
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.
mbf_in_mn
Minneapolis, MN
Montana Fly Girl
Location:Montana
Age:55–64
Weight:125–150 lbs.
Height:5'4"
Rated 2.0 out of 5 stars
2 years ago

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.

Age:55–64
Weight:125–150 lbs.
Height:5'4"

Overall Fit Rating

Runs SmallRuns Large
pihiker
Location:Boise, ID
Age:55–64
Weight:125–150 lbs.
Height:5'4"
Rated 3.0 out of 5 stars
3 years ago

Great for active adventures

Received free product

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.

Age:55–64
Weight:125–150 lbs.
Height:5'4"

Overall Fit Rating

Runs SmallRuns Large
TMN
Location:Reno, NV
Age:35–44
Weight:125–150 lbs.
Height:5'6"
Rated 5.0 out of 5 stars
5 days ago

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.

Age:35–44
Weight:125–150 lbs.
Height:5'6"

Overall Fit Rating

Runs SmallRuns Large
Jagjas
Location:Tampa, FL
Age:45–54
Weight:125–150 lbs.
Height:5'8"
Rated 4.0 out of 5 stars
2 years ago

Almost Perfect

Received free product

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!

Age:45–54
Weight:125–150 lbs.
Height:5'8"

Overall Fit Rating

Runs SmallRuns Large
mbf_in_mn
Location:Minneapolis, MN
Age:35–44
Weight:125–150 lbs.
Height:5'0"
Rated 3.0 out of 5 stars
2 years ago

Wish these were seamless

Received free product

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.

Age:35–44
Weight:125–150 lbs.
Height:5'0"

Overall Fit Rating

Runs SmallRuns Large
MJB
Location:Portland Oregon
Age:35–44
Weight:225–250 lbs.
Height:5'7"
Rated 4.0 out of 5 stars
2 years ago

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.

Age:35–44
Weight:225–250 lbs.
Height:5'7"

Overall Fit Rating

Runs SmallRuns Large
aandm200
Age:25–34
Weight:200–225 lbs.
Height:5'7"
Rated 5.0 out of 5 stars
2 years ago

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.

Age:25–34
Weight:200–225 lbs.
Height:5'7"

Overall Fit Rating

Runs SmallRuns Large
Heather
Height:5'6"
Age:25–34
Weight:150–175 lbs.
Rated 3.0 out of 5 stars
2 years ago

these are briefs

These are less expensive than some wool underwear so I bought them. The wool os wonderful, breathes well, dries quickly. But these are not bikini. These are briefs. Very tall. The large elastic stays put but isn’t flattering on my hourglass figure. I feel like these are a gateway pair. There a couple of dollars more affordable than others but too tall.

Height:5'6"
Age:25–34
Weight:150–175 lbs.

Overall Fit Rating

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Effie
Location:Finger Lakes
Age:55–64
Weight:100–125 lbs.
Height:5'4"
Rated 5.0 out of 5 stars
1 year ago

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.)

Age:55–64
Weight:100–125 lbs.
Height:5'4"

Overall Fit Rating

Runs SmallRuns Large
msbethgrace
Location:Vancouver
Age:35–44
Weight:100–125 lbs.
Height:5'4"
Rated 4.0 out of 5 stars
2 years ago

Comfy and colorful

Received free product

The first thing I'd like to mention is how comfortable these are, I don't even notice these are on - no weird snagging or pulling, just overall nice feeling. I do not own many wool items so am surprised at the quality of this product - not itchy, not too warm. As it is a wool product, I chose to wash by hand and air dry, and it dries fairly quickly (this would be great for a camping/backpacking trip). I will note that when I first tried it on pre-washing, the item sagged in the back, and it is more high waisted than I'm used to. It feels like it runs a bit big. After that first wash, I haven't noticed anymore sagging. I'm tempted to put it in the drier on a higher cycle than recommended to see if it shrinks up some more, but not too much (which has happened in the past with other wool items). I used these underwear while walking, doing yoga, hiking, and working a normal day. I have no complaints, they seemed invisible whilst wearing them! If you're looking for a versatile underwear to add to your closet, then this could be a good option for you.

Age:35–44
Weight:100–125 lbs.
Height:5'4"

Overall Fit Rating

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1 - 10 of 52 Reviews

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