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REI Co-op Active Bikini Review

This is an all-around knockout, with high scores in every category and an affordable price tag
Editors' Choice Award
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Price:  $17 List | $16.95 at REI
Pros:  Breathable, super comfortable, affordable
Cons:  Nothing!
Manufacturer:   REI Co-op
By Lauren DeLaunay ⋅ Senior Review Editor  ⋅  Mar 10, 2020
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#1 of 9
  • Comfort - 35% 9
  • Fit - 30% 9
  • Drying Time - 25% 9
  • Packability - 10% 9

Our Verdict

After years of testing the women's travel underwear category, we brought in a few brand-new models for 2020. One of these, the REI Co-op Active Bikini, was immediately intriguing. As the only product in this review made with polyester, we didn't know what it would feel like — but for the killer price, we had to check it out. And let us just say: as soon as we laid our hands on these undies, we were sold. The Active Bikini is super soft, incredibly light, and amazingly quick to dry. We love the fit, which is true to size with moderate yet flattering coverage. Even if this product weren't one of the most affordable options in this review, we'd still be blown away by its all-around performance, which is why we're happy to call it our Editors' Choice Award winner.

Compare to Similar Products

Our Analysis and Test Results

The REI Active Bikini has everything we're looking for in a great pair of travel underwear. A great pair of undies lets you forget that you even have them on, and that's precisely how we feel wearing this award-winning product.

Performance Comparison

Washing the REI Active Bikini after lots of use in Cochamo  Chile.
Washing the REI Active Bikini after lots of use in Cochamo, Chile.


Comfort can mean different things to different people, but here at OutdoorGearLab, we've identified a few characteristics that help us describe each product's performance in language we can all agree on. In this category, we evaluated each garment's material construction and breathability.

The Active Bikini is one of the only products we tested mostly made of polyester. While some of the products we tested are wool, most of them are nylon. At 86% polyester and 14% Spandex, we didn't know what to expect, but what we found was one of the best hand-feels in this entire review. The Active is incredibly soft, and we never wanted to take them off. From the waistband to the seams, we were truly blown away.

A close-up of the soft polyester that contributed to the REI Active Bikini's performance.
A close-up of the soft polyester that contributed to the REI Active Bikini's performance.

While there are some other synthetic products in this review that are nearly as soft, none seem to have quite the breathability. This product is thin, and after weeks in the Chilean rain forest, we were really impressed with the performance. The Active is one of the most breathable undergarments we've tested, leaving us feeling fresh even when the temperature spiked.


When our testing team brainstormed the metrics that would define the travel underwear category, we knew instantly it was all about feel. But the more we tested, the more we realized how many things work together to make something comfortable. So, we separated "fit," which we've defined here as the cut, shape, and stretch of a garment from the material feel.

Our team loves the fit of the Active Bikini for a whole host of reasons. First, we agreed that the fit is spot-on for sizing, which is always appreciated. Having tested a few different cuts, from bikini to hipster to boy shorts, we find this one to have a great blend of coverage and style. Even though this product is offered in different cuts, including ones with more coverage, we really like that the bikini model is made with active outings in mind. We found excellent stability with the Active — meaning we never, ever had a wedgie. And after weeks of hiking in the Patagonian rain forest, we know that staying wedgie-free is an absolute must-have.

Hanging the REI Active in our hostel bathroom to dry  we see its balance between coverage and style.
Hanging the REI Active in our hostel bathroom to dry, we see its balance between coverage and style.

Compared to other products in our review, the Active finds a fantastic combination of coverage without also having too-snug leg openings. The just-right leg openings also create a more seamless visual effect. While it's not the most visually panty line-free, we find it to be much more appealing than many of the other bikini or hipster models we tested. The waistband is also more comfortable than many others we tested. It's more integrated into the design and is made of the same material blend, making for a seamless feel.

Finally, talk about stretch! Most of the undies in this review are impressively stretchy, but the Active is especially so. The great light and stretchy fit definitely make it out first pick for big, active days in the mountains and on the trails.

Drying Time

The products we picked for this review all have one thing in common: they're meant to take us somewhere. And whether that's around the world with nothing but a backpack or deep into the wild, at some point, we need to be able to wash and dry our clothes quickly so we can get right back to adventuring. For this category, we did multiple rounds of side-by-side testing to see which products dried faster than others; additionally, we took copious notes throughout our weeks of wear and tear.

The Active Bikini is one of the fastest drying models in this review. It's super-light, which is typically an indicator of drying speed. That aside, it's the only polyester product we reviewed, and while we're not materials scientists, we do think that this has something to do with the Active's top-notch performance. In addition to drying fast on the clothesline, we were constantly impressed with how dry we stayed even when drenched with sweat. For traveling and moving in hot, humid environments, the Active is absolutely our first choice.

The REI Active was easy to wash and dry while on the go in Chile.
The REI Active was easy to wash and dry while on the go in Chile.


The packability of a travel product tells us a lot. We measure both weight and folded dimensions to get a full sense of how easy it is to bring each product along for a variety of travels.

Weighing in at just .6 ounces, the Active is one of the very lightest products in this review. While we're talking about fractions of ounces, everything adds up, and we certainly noticed the lightness of this product — some of its competitors weigh twice as much. You can head into the backcountry or on a multi-month journey with several of these in your pack, guilt-free.

Weighing the REI Active to get an objective measurement on packability.
Weighing the REI Active to get an objective measurement on packability.


One of OutdoorGearLab's most important practices when reviewing gear is to test each product without considering its price first. Value is important, but a great product is just a great product, regardless of price. After we assign each product an overall score, we factor the price back in to come up with overall value. Luckily for the REI Active, it's not only the highest-scoring product in this review (cinching it our Editors' Choice Award), but it's also one of the least expensive. It's rare to find that combination, so we dug and dug to try to find loopholes that may have deceived us. But, after weeks of continuous testing, it's true: this product has incredible value.


The REI Active Bikini is taking home our highest honor for one simple reason: it has top scores in every single category. There's no compromise with this product. It's soft, stretchy, breathable, lightweight — all at an excellent price. It's not always the case that we find a product that we love for every occasion, but in this case we did. Five stars.

Laundry day in Cochamo is easy with the quick-drying REI Active Bikini!
Laundry day in Cochamo is easy with the quick-drying REI Active Bikini!

Lauren DeLaunay