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      Front view of woman in black v-neck one-piece bathing suit with People Tested badge | alexhakim16 / M alexhakim16 / M
      Back view of woman in black one-piece bathing suit | alexhakim16 / M alexhakim16 / M
      Back view of woman in red one-piece bathing suit | Kaydence / S Kaydence / S
      Side view of woman in black v-neck one-piece bathing suit | alexhakim16 / M alexhakim16 / M
      Back view of plus-size woman in black one-piece bathing suit | ariellamayamendes / 2XL ariellamayamendes / 2XL
      Front view of woman in colorful v-neck one-piece bathing suit | blessedgoddess__ / XS blessedgoddess__ / XS
      Woman in a red swimsuit by a pool with informational text about the product.
      Woman wearing a black swimsuit with text highlighting features on a white background
      Woman in a red swimsuit on a beach with text about swimwear fit.
      Woman in a red swimsuit standing in water with a neutral background
      Two women wearing black swimsuits on a beach with a lifeguard stand in the background.
      Circular portraits of four women with different body types modeling swimwear, plus a pink badge 'see it on busts of different sizes!'
      Six diverse models wearing black bathing suits in a grid showcasing different fits and sizes

      PATENTED SWIM THAT FITS LIKE UNDIES®

      4.6/ 5
      $98.95 $98.95
      Color: Abyss
      Size: S
      Customers say this one-piece swimsuit fits like seamless underwear and provides excellent tummy control without feeling restrictive. The material is soft, smooth, and high-quality, creating a flattering silhouette that enhances curves and makes the bottom look great. Many appreciate how it doesn't dig into skin or create bulges like other suits. Common feedback includes the need to size up for proper fit and stretch the suit before wearing. Some mention concerns about the low-cut front being too revealing and limited bust support for larger chests. The suit runs cheeky in coverage, which some love while others prefer more coverage. Overall, customers find it confidence-boosting and plan to purchase additional colors.
      free shipping on US orders over $95
      If you want an absolute dynamite, bombshell fit, Bellows is IT for you. A super secure, deep V neckline with removable cups combines with a high-cut leg and...

      If you want an absolute dynamite, bombshell fit, Bellows is IT for you. A super secure, deep V neckline with removable cups combines with a high-cut leg and a sculpting, smoothing waist for a confidence-boosting fit. No digging, no pinching, no squeezing into your sides...Bellows makes for the perfect flattering one piece swimsuit OR bodysuit. 

      be sure to take our size quiz! if you still need size help, check out our size chart here.

       

      • Ultra-comfortable swimsuits designed to fit like no-show underwear, eliminating digging at the waist and hips.
      • Better-than-seamless swimwear with raw-cut edges to create a smooth, flattering bathing suit silhouette.

      • Smoothly bonded, NOT sewn with tight seams that squeeze, for a second-skin fit and feel. An inner grip strip keeps the suit secure without digging.


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        ships from CT, USA
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        14-day returns
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        1 free exchange

        see it on

        Woman in red swimsuit looking over a railing with turquoise water and a volcanic island in background
        L
        Woman in red one-piece swimsuit standing on pool deck next to tropical plants, smiling toward the camera.
        Size: S
        Woman in black swimsuit smiling at camera beside a backyard pool
        Size: 2XL
        Person in a red swimsuit climbing a boarding ladder onto a boat over blue water.
        Size: XS
        size & fit info

        Bust support

        least most
        When you get your onewith
        Torso wearing black bikini-style underwear showing arrows pointing to hips

        1. your correct size SHOULD dig in a bit to start, then...

        Torso and hands adjusting black bikini-style underwear at the hips to show fit

        2. after warming up your onewith (aka giving it a stretch)

        Torso wearing black bikini-style underwear

        3. your onewith will be smooth like no-show undies!

        Shipping & Returns

        RETURNS.

        • 1 free exchange within 14 days of delivery for eligible US orders.
        • refunds are available within 14 days of delivery for eligible US orders (fee applies).
        • items purchased at a discount of 30% or more are eligible for store credit only.
        • items marked final sale are always, you guessed it, final sale!
        • international orders are always final sale. see our full returns policy here.

        SHIPPING

        • free standard shipping on US orders over $95
        • priority + express shipping also available!
        • international shipping available, rates and duties calculated at checkout
        • Shipping Protection, offered at checkout, is HIGHLY recommended! It covers lost, damaged, stolen, and stuck-in-transit packages
        Product details
        • designed in USA, made in China
        • Patented, US Patent No. 12,537,039
        • LATEX INFO: we cannot guarantee that the inner grip strip of our suits is entirely free of latex. If you have a latex sensitivity or allergy, we recommend exercising the same caution you would typically use when assessing whether to wear a product that may contain latex.
        • 80% nylon, 20% elastane
        • hand wash only, lay flat to dry
        Swimsuit care
        • Hand wash in cold water as soon as you can after use (rinsing in the shower is fine!)
        • DO NOT machine wash.
        • Lay flat to dry, do not hang.
        • Do not dry clean, iron, or machine dry (even on a delicate cycle...) as this can, and most likely will, damage your onewith.
        • Hot tubs and chlorinated pools with harsh chemicals can impact the quality and longevity of any swimwear, so it’s best to avoid them if you want to keep your swim in tip-top shape.
        • If you wear your onewith under normal clothes, keep in mind that friction can create pilling/snagging. We prefer to wear our onewith under beach cover-ups/sarongs, which are created to be worn with swim.
        • Sunless tanners, suntan lotions, oils, and harsh chemicals can ruin your onewith - ensure to not get these products in contact with any swim/garments!

        Pair this with...

        Instructions Recommended Details Reviews FAQs
        Three pastel pink bubbles with sparkles and subtle iridescent highlights
        Three pastel pink bubbles with sparkles and subtle iridescent highlights

        See our swim in your size

        Woman in a black onewith bikini sitting on rocks by the ocean
        andrypena / XXS + XXS
        Woman in a red onewith one piece swimsuit standing on a boat with blue water in the background
        kareenasinghh / XS
        Woman standing on a rocky shoreline wearing a bright blue bikini, hands behind her head
        kareenasinghh / XS + XS
        Woman in a red onewith one piece swimsuit standing on a boardwalk with greenery in the background
        carolyn.mhickman / S
        Woman wearing a blue onewith bikini standing against a wooden wall.
        dayj.doll / S + S
        Woman wearing a blue onewith bikini top in a pool
        megdlyn / S
        Woman in a blue onewith bikini and sunglasses standing on a balcony with a view of a marina
        ivana_ferro / S + M
        Woman in a black onewith bikini standing on a beach
        alyssa.models / S + M
        onewith founder Hayley wearing a onewith black one piece swimsuit taking a mirror selfie
        onewithswim / S
        Woman in a black onewith one piece swimsuit standing on a beach with water in the background
        ahmeimae / S
        Woman wearing a black onewith one piece swimsuit in front of the ocean
        ahmeimae / S
        Woman wearing a black bikini on a beach
        alexhakim16 / S + M
        Woman in a black onewith bikini standing on a beach with water and sky in the background
        ahmeimae / S + M
        Woman wearing a brown onewith bikini with a bag
        onewithswim / S + S
        Woman in a onewith bikini and hat on a beach at sunset
        carolyn.mhickman / S + S
        Woman in a black onewith bikini and hat standing in the ocean
        emily_shultis / S
        Woman in a black onewith bikini posing by a pool
        traceydoes_ / S + M
        Woman wearing a blue onewith bikini taking a mirror selfie
        onewithswim / S + S
        Woman wearing a black onewith bikini taking a selfie
        lordnavji / M + M
        Woman in a blue onewith bikini standing on a dock by water
        ahmeimae / M + M
        Woman reclining by a pool wearing a black bikini
        traceydoes_ / S + M
        Smiling woman kneeling on wet sandy beach, wearing a black bikini, hands in her hair
        anaidalyramos / M + M
        Woman in a black onewith bikini standing against a teal door.
        Anaidayl / M + M
        Reclining woman wearing a black bikini top on wet rocks, showing necklaces and a ring
        ahmeimae / M
        Woman in a blue onewith bikini and pink hat by a pool
        ivana_ferro / S + M
        Woman in a black onewith bikini sitting on a beach with ocean in the background
        alyssa.models / S + M
        Woman in a black onewith bikini standing on a beach with water and sky in the background
        ahmeimae / M
        Woman in a black onewith bikini sitting on a counter
        anaidalyramos / M + M
        Woman in a black onewith bikini on a boat
        ivana_ferro / S + M
        Woman in a red onewith one piece swimsuit standing by the ocean
        ashleyyharveyy / L
        Woman sitting on a dock by a body of water wearing sunglasses and a black onewith bikini top.
        ceciliakauffmanharris / L
        Woman wearing a black onewith bikini standing on a beach
        chloewoz / XL
        Woman in a blue onewith bikini standing in a pool with a flower in her hair
        summerleilani_ / XL
        Woman wearing a black onewith bikini standing on a balcony.
        chloewoz / XL + XL
        Plus-size woman in a black bikini leaning on a white porch railing, smiling at the camera
        chloewoz / XL + XL
        Woman wearing a black onewith bikini standing on a balcony overlooking a beach with palm trees.
        wendyfrita / 2XL + XL
        Woman wearing a black onewith one piece swimsuit in a pool
        gracedotymusic / 2XL
        Woman in a blue onewith bikini holding a drink under a palm tree
        cheyenneolson / 2XL
        Woman wearing a black onewith one piece swimsuit taking a mirror selfie.
        gracedotymusic / 2XL
        Woman in a black onewith bikini standing on a beach
        gracedotymusic / 2XL + 2XL
        Woman wearing a black onewith bikini sitting on a stool indoors.
        gracedotymusic / 2XL + 2XL
        Woman in a blue onewith bikini standing on a boat with rocky cliffs and blue water in the background
        Marisa / 2XL + 2XL
        Woman in a black onewith bikini standing on a rocky beach with houses and trees in the background.
        tatumblinncoffey / 3XL + 3XL
        Woman wearing a black onewith bikini standing on a beach with ocean in the background
        misscurvygirl_love / 2XL + 3XL
        Woman in a black onewith bikini standing on a sandy beach with water and boats in the background.
        ariellamayamendes / 2XL + 3XL
        trying on your onewith

        What to know when your onewith arrives!

        What to know when your onewith arrives!

        Torso wearing black bikini-style underwear showing arrows pointing to hips

        1. your correct size SHOULD dig in a bit to start, then...

        Torso and hands adjusting black bikini-style underwear at the hips to show fit

        2. after warming up your onewith (aka giving it a stretch)

        Torso wearing black bikini-style underwear

        3. your onewith will be smooth like no-show undies!

        1 FREE exchange on eligible US orders

        Gift box icon

        size inclusive (XXS-3XL)

        Two-person users icon indicating user accounts

        patented, US Patent No. 12,357,039

        Heart outline with check mark indicating selected/favorited
        Three pastel pink bubbles with sparkles and subtle iridescent highlights
        Three pastel pink bubbles with sparkles and subtle iridescent highlights
        Three pastel pink bubbles with sparkles and subtle iridescent highlights

        traditional swimwear
        vs. onewith swim

        goodbye, tight seams and elastic. hello smooth, patented swim that fits like your favorite undies.

        Woman wearing a black scoop‑neck bikini top and high‑rise black bikini bottoms on a neutral gradient background with decorative sparkle stars after
        Woman in a black two-piece swimsuit (crop top, high-waist bottoms); torso and upper thighs visible. before
        Woman reclining in a black two-piece swimsuit on sunlit sandy surface, relaxed pose
        Edgeless... Better
        Than Seamless!
        dig-free + elastic free
        Lay-flat, second-skin fit
        Three pastel pink bubbles with sparkles and subtle iridescent highlights

        why choose onewith?

        2 layers of fabric, smoothly bonded, not sewn with seams that squeeze.

        Three women in swimsuits posing against a vertical wooden-panel background
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        Shark Tank TV logo
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        4.6
        Rated 4.6 out of 5 stars
        Based on 55 reviews
        Total 5 star reviews: 41 Total 4 star reviews: 10 Total 3 star reviews: 2 Total 2 star reviews: 2 Total 1 star reviews: 0
        93%would recommend these products
        55 reviews
        • AC
          Amy C.
          Verified Buyer
          Reviewing
          Bellows Plunge High-Cut One Piece
          I recommend this product
          Rated 5 out of 5 stars
          7 hours ago
          Confidence I Haven’t Felt in Years

          I honestly didn’t expect a swimsuit to make me feel this way.

          Like so many women, I’ve struggled with body image - especially navigating the changes that come with menopause. Finding something that feels both comfortable and flattering has felt nearly impossible… until this.

          From the moment I tried on my first suit from onewithswim.com, I was blown away. The fit truly feels like underwear - in the best way. It’s soft, supportive, and just works with your body instead of against it.

          I ended up ordering a few more styles immediately, and I wore one on my most recent vacation. For the first time in a long time, I felt genuinely confident in a swimsuit. Not adjusting, not overthinking - just enjoying myself.

          That feeling is priceless. I haven’t felt that way in years!

          If you’ve been on the fence, this is your sign to hit "submit order" STAT!

        • RW
          Ruth W.
          Verified Buyer
          Reviewing
          Bellows Plunge High-Cut One Piece
          I recommend this product
          Rated 5 out of 5 stars
          2 weeks ago
          Fits perfectly in all the right places!

          I’m honestly so impressed with this one piece. It fits in all the right places. I got a size large because I’m naturally top heavy,32” under bust and 41.5” bust, and usually with larges it ends up being loose on the bottom since I’m more P shaped but this fit everything perfectly.

          It really flatters my cleavage and doesn’t make them look saggy at all which is huge for me. I can definitely see myself wearing this as a bodysuit too with jeans, not just a swimsuit.

          The material is nice and thick which I love because it feels really good quality and secure. I can’t wait to wear it this summer.

          I would definitely buy more colors. If they ever release a lavender color I’m jumping on it immediately.

          I actually first saw this brand on Shark Tank and have been getting emails for over a year. I finally decided to try it when there was a sale and I’m so glad I did. Definitely a forever customer and I’ll be telling everyone about it!

        • RS
          Rita S.
          Verified Buyer
          Reviewing
          Bellows Plunge High-Cut One Piece
          I recommend this product
          Rated 5 out of 5 stars
          3 weeks ago
          Fits Well

          I was looking for a swim suit that was not heavy and dries fast. This is it

        • RH
          Rafaela H.
          Verified Buyer
          Reviewing
          Bellows Plunge High-Cut One Piece
          I recommend this product
          Rated 5 out of 5 stars
          1 month ago
          Body tight

          I love the control on my body. I’m heavy chested and this is exactly what I been searching for. I look out together in all the right places . I wish there were more colors .

        Two women in black one-piece swimsuits standing at a lifeguard stand on the beach.
        Three pastel pink bubbles with sparkles and subtle iridescent highlights
        Three pastel pink bubbles with sparkles and subtle iridescent highlights

        frequently asked questions

        does that strip inside your suits contain latex?

        onewith can not guarantee that the inner grip strip inside of our suits does not contain trace amounts of latex. Therefore, if you have a latex or adhesive sensitivity/allergy, we recommend you exercising the same caution and sensibilities you would take in general when determining whether or not to use or wear a product that may contain latex or adhesive, should you have a known issue with these substances.

        what size am I?

        in general we are true-to-size. we have a handy-dandy size quiz on every product page. take it once and it will give you your best size for each & every style!
        you can also reference our size guide here. there are fit notes on every product page to help you choose your best size!

        where are your suits designed & made, and what kind of fabric is it?

        we are a US-based company; our suits are designed in North America and made in China. all pieces are made of 80% nylon, 20% elastane.

        are your suits see-through?

        our suits are 2 layers of fabric just like any other swimwear...it's just bonded, not sewn with tight seams, so that it lays flat on your skin like your favorite no-show underwear. with that, onewith is the same opacity as all other swimwear. if you are sensitive to ANY sheerness when wet, as with ALL swim, opt for a darker color.

        when are you restocking?

        sign up for restock notifications on the product pages of the item you want, and be sure to follow us on Instagram for the latest & greatest of all things onewith!

        are your suits thin? like, will they cause 🐫toe?

        our suits are 2 layers of fabric just like any other swimwear; it's just bonded, not sewn with tight seams. so while it may appear to be thinner, it is actually the same thickness of material as most traditional swim. so if you're worried about a case of 🐫toe, while we can't guarantee our suits are frontal-wedgie-free, so-to-speak as every person's body is different...we can say that there is no reason why our suits would cause it more than any other swimwear. if you're ever worried about anything showing through, a general swim tip is to opt for a darker color or a suit in a pattern.

        why don't you have more colors/styles?

        we design by demand and data. if we get enough requests for something & it stands to reason it might do well, we might just make it! for new color requests, please watch this video for more info on why we don't make a lot of colors.

        if I don't know my size, can I just order multiple sizes and return what doesn't work?

        ⛔ we strongly discourage bracketing (ordering multiple sizes or styles with the intention of returning what doesn't work) as well as high-quantity first orders. while we completely understand the desire to find your perfect fit, this practice creates real inventory challenges for us as a small business, and also compromises hygiene best practices.

        we're big believers in conscious consumerism and encourage small, mindful first orders. once you've found your perfect size and your new favorite swim, we absolutely love it when you stock up — just please do so with the intention of keeping your order, not returning the extras. we know this kind of large-order flexibility may feel standard with bigger retailers, but we ask that you consider how bracketing and high-volume returns affect a small business, its customers, and the environment.

        returns of 4 or more items per order will be subject to a $15.95 processing fee in addition to the standard return fee.

        what size am I?

        in general we are true-to-size. please reference our size guide here. also, TAKE THE SIZE QUIZ! it is so helpful, we made sure of it :)

        what happens if my swimsuit doesn't fit? can I return/exchage?

        we offer a 14-day return/exchange policy on all swimwear, beginning the day of carrier-confirmed delivery. a customer's first exchange is free to ensure you find your perfect onewith fit. returns for store credit are also free; returns for a refund incur a $12.95 fee (additional fees apply for high-volume returns). all returns and exchanges must come back in original, unworn condition with the hygiene liner intact. Read more about the onewith return policy here.

        in general our suits run true-to-size, but be sure to take the size quiz linked on each product page. the quiz is tailored to each style, so you'll always get the most accurate recommendation.

        ⚠️ NOTE: ITEMS MARKED FINAL SALE + INTERNATIONAL ORDERS ARE ABSOLUTELY, POSITIVELY FINAL SALE. no returns, no exchanges, no exceptions.

        i wear [this] bra size. what size top am i?

        because we make swimwear that feels like underwear, our swim tends to be a great fit on so many bust sizes... from AA to J cup and beyond! check the product images to see our tops on a range of bust sizes. check out this blog post for a comprehensive guide on how to best pick your top size. pro-tip for choosing your onewith bikini top size: we don't size by cup! we'd recommend going with the same size top you would for a camisole.

        Can I see a certain style on a body type similar to mine?

        we offer lots of content of our swim on different bodies all over our site + socials! Namely, we have a onewith wearer gallery all of our product pages, our ‘plus size’, ‘try-ons’, ‘customers’, and fuller bust’ highlights on Instagram, the coverage/support meter on product pages,, size guide page, and more! we have so much content with lots of different representation.

        do you ship internationally?

        onewith is proud to offer international shipping!

        all international sales are positively FINAL. no returns or exchanges are available for international orders.

        shipping rate to your country is calculated at checkout, and is set by the carrier. in most cases, this rate also includes duties/customs! some exclusions may apply.

        I placed an order and was charged, but can't find a confirmation

        it's possible you only included a phone number for contact info when you placed your order. in this case, all order updates would be sent via text. if you're not able to find any order notifications via text, please check any other email addresses you have access to. if you're still not able to find the confirmation, please send an email to info@onewithswim.com and our team will be happy to assist you!

        what's your return/exchange policy?

        swim is an intimate garment, and therefore deeply personal. for that reason, we're happy to offer returns and exchanges on domestic, non-final sale orders — with a few conditions.

        exchanges: onewith offers 1 free exchange on eligible US orders within 14 days of carrier-confirmed delivery.

        returns: onewith offers returns on eligible US orders within 14 days of carrier-confirmed delivery. returns for store credit are free; returns for a refund are subject to a $12.95 fee. additional fees apply for high-volume returns (4+ items).. items purchased at a discount of 30% or more are eligible for store credit only. see our full return policy for details.

        final sale: items marked final sale and all international orders are final sale — no returns, no exchanges, no exceptions.

        Woman in blue bikini standing on porch holding sign reading
        @onewithswim
        Woman wearing a black onewith bikini
        @itsmisslys
        Woman reclining on rocky shore in a black bikini, wearing layered gold necklaces and rings, hand on chest.
        @ahmeimae
        Woman in a black onewith bikini posing by a pool
        @traceydoes_
        Woman in a brown swimsuit top wearing a necklace and an orange hibiscus in her hair, smiling beside a potted hibiscus.
        @ivana_ferro