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      The most flattering swimsuit you'll ever wear.

      No elastic, no edges, no seams digging in to cut at your shape. onewith is bonded instead of sewn, so it lays flat against your skin and gives you one smooth, uninterrupted line. The result is a second-skin fit that flatters everywhere your old swim used to pinch and pull.

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      10% Off Your First Order with code likeundies

      over 50,000 happy customers

      the onewith community

      Woman in straw hat and mauve swimsuit sitting at the pool edge reading a book, towel and snacks beside her.

      Size: S + M

      Woman in a black bikini sitting on a sandy beach, leaning on one arm and looking down.

      Size: S + M

      Front view of blue onewith two-piece swimsuit on plus-size model with knot-front top and raw-cut bottoms at indoor pool

      Size: L

      Woman in red swimsuit looking over a railing with turquoise water and a volcanic island in background
      Size: 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: 3XL
      Size: 3XL / 3XL
      Woman in a bright blue bikini looking over her shoulder, standing against a vertical wood-paneled wall
      Size: S / S
      Size: S / M
      Size: XS / XS
      Size: S / S
      Woman in black bikini standing on rocky beach, smiling; ocean and palm trees in background.
      Size: L
      Woman wearing blue bikini top and sunglasses, smiling with arm tattoos, outdoors by trees and sky.
      Size: S
      Size: 2XL
      Woman in blue bikini and sunglasses holding a red drink cup under a palm tree.
      Size: 2XL
      Woman in black bikini standing on sandy beach path near wooden posts under a cloudy sky
      Size: XL / XL
      Three pastel pink bubbles with sparkles and subtle iridescent highlights

      meet the best-sellers

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      5.0/ 5

      What people are saying

      skeptic turned fan

      "Was very skeptical on the fit, but these truly do feel like your no show underwear!"

      Maritza R.

      love them

      “it actually feels secure. I forgot I was even wearing swim.”

      Laura S.

      they're perfect

      "I’m obsessed, genuinely the best fitting bathing suit bottoms I’ve ever owned."

      Kylie B.

      as seen on
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      why we exist

      onewith started on an apartment floor, buried under a pile of suits that all had one thing in common: they didn't fit right. So founder Hayley built one that did. Years of R&D and a patented construction later, the result is better-than-seamless, edgeless swimwear built around one obsession: making women feel at home in their bodies at the beach.

      Three pastel pink bubbles with sparkles and subtle iridescent highlights

      The onewith Difference

      Most swimwear cuts into you with seams and elastic that break up your line and leave marks. onewith doesn't. Our edges are bonded instead of sewn, so the suit lays flat against your skin for one smooth, uninterrupted line that flatters from every angle.

      Bonded, Elastic-Free Edges

      Warm-Up Stretch Fit

      Inner Grip Strip

      Beyond-Seamless Look

      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

      the fit you've always wanted

      A smooth, second-skin fit that follows your shape instead of fighting it. No digging, no bulging at the edges, just a clean line that makes you look and feel your best.

      The most flattering swimsuit you'll ever wear

      Dig-free and edgeless

      Elastic-free, better-than-seamless

      A fit that's truly onewith your body

      Three pastel pink bubbles with sparkles and subtle iridescent highlights
      Three pastel pink bubbles with sparkles and subtle iridescent highlights

      See it 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 black one-piece swimsuit standing on a muddy beach with hands on hips, wooden pilings and shallow water behind her.
      ahmeimae / S
      Back view of onewith Idlewild High-Neck One Piece in black showcasing low scoop back and high-cut leg with ocean background
      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
      Three-quarter view of Hampton bottom in black on a model showcasing high-rise, full-coverage fit with raw-cut edges at poolside
      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
      Mirror selfie of Idlewild High-Neck One Piece in Abyss black on model showcasing high neckline and full-coverage fit
      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
      hayleyhermsofficial / 3XL
      Woman in a black onewith bikini standing on a sandy beach with water and boats in the background.
      ariellamayamendes / 2XL + 3XL

      We're confident you'll find your fit.

      1 free exchange on eligible us-orders

      14-day returns on eligible us orders

      ships fast from ct, usa

      all swim

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      1 FREE exchange on eligible US orders

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      size inclusive (XXS-3XL)

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      patented, US Patent No. 12,537,039

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