Name: Penfield High-Waisted Thong Bikini Bottom
Brand: onewith swim
SKU: 1W-PE-JE-XXS
Price: 49.95 USD
Availability: InStock
Rating: 4.6 (31 reviews)

Back view of Penfield high-waisted thong bikini bottom in Jelly blue showcasing high-rise waist and thong back on white background | alexhakim16 / M

alexhakim16 / M

alexhakim16 / S + M

ariellamayamendes / 3XL

Woman in a blue bikini with text about Penfield's target audience.

Woman wearing a black bikini with text highlighting features on a white background

Three women in swimsuits standing on a beach with text about size guidance.

Woman wearing a blue bikini standing on rocks by the water

Woman in a black bikini standing by a pool with text indicating size information.

Two women in black bikinis standing side-by-side for a bikini bottom comparison

Six diverse models wearing black bathing suits in a grid showcasing different fits and sizes

PATENTED SWIM THAT FITS LIKE UNDIES^®

4.6/ 5 31 reviews

$49.95 $49.95

Color: Jelly

Size: XXS

XXS

2XL

3XL

free shipping on US orders over $95

A dipped high-waist front and a thong back make Penfield an absolute icon. Designed for the woman who wants a daring, cheeky fit that still looks effortless ...

A dipped high-waist front and a thong back make Penfield an absolute icon. Designed for the woman who wants a daring, cheeky fit that still looks effortless (and feels edgeless, like no-show undies, of course). With our signature inner grip tape and elastic-free, better-than-seamless-swim bonding, Penfield is curve-baring perfection.

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.

ships from CT, USA

14-day returns

1 free exchange

see it on

Woman in black bikini standing on balcony overlooking a sunny beach with palm trees and ocean — Size: 2XL / XL

size & fit info

Booty coverage

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

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 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 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 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

Smiling plus-size woman in a black bikini standing on the beach with the ocean behind her, hand on strap. — 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!

1 FREE exchange on eligible US orders

size inclusive (XXS-3XL)

patented, US Patent No. 12,357,039

more swim you'll love

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

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

4.6

Rated 4.6 out of 5 stars

Based on 31 reviews

Total 5 star reviews: 23 Total 4 star reviews: 6 Total 3 star reviews: 1 Total 2 star reviews: 0 Total 1 star reviews: 1

94%would recommend these products

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31 reviews

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PH
Peggy H.
Verified Buyer
Reviewing
Penfield High-Waisted Thong Bikini Bottom
I recommend this product
Rated 5 out of 5 stars
2 days ago
Fits as described
I love the fit. The bottoms stay in place and fit smoothly against the skin.
Was this helpful?
G
George
Reviewing
Penfield High-Waisted Thong Bikini Bottom
I recommend this product
Rated 5 out of 5 stars
2 weeks ago
Wife love it, now I am curious!
I bought it as a surprise, trying to measure my wife the best I could without telling her. She loved it, especially how comfortable they are! Now you got me curious of when are you releasing a men's line because this completely new philosophy of fitting got me very interested!!
Was this helpful?
SM
Susana M.
Verified Buyer
Reviewing
Penfield High-Waisted Thong Bikini Bottom
I recommend this product
Rated 5 out of 5 stars
2 weeks ago
Sexy!
I love! It's what I was hoping for. Covered my belly section with not going over my belly button. The thong definitely brought out a booty I thought I didn't have. It doesn't dig in on the love handles. Can't wait to ware it in Vegas! For reference I'm 5'6 175lbs bought an XL like recommended through sizing questions.
Was this helpful?
HM
Harmony M.
Verified Buyer
Reviewing
Penfield High-Waisted Thong Bikini Bottom
I recommend this product
Rated 5 out of 5 stars
1 month ago
AMAZING
i love how these fit. so worth it
Was this helpful?

Two women in black one-piece swimsuits standing at a lifeguard stand on the beach.

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.

free shipping on US orders over $95

ships from CT, USA

14-day returns

1 free exchange