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onewith size guide

Ready to find your perfect onewith fit? Just click the size quiz button on any product page, answer a few simple questions. Once completed, your best size will populate, tailored to each and every style on our site for all our products as you continue to shop. 🎉

Now, remember—everyone's unique, and preferences, along with the human body, are more dynamic than any size chart or quiz could ever capture. That being said, our sizing quiz is the next best thing to actually trying on our suits in person 😉🔍 

Disclaimer: While we strive to provide the most accurate sizing guidance possible, please note that individual fit preferences and proportions may (read: WILL) vary. Buying the size that the size quiz suggests does not guarantee your fit.

If you have any further questions or concerns, our dedicated customer support team is always here to assist you (chat us, DM us, email us, etc!) and, we offer 1 free courtesy exchange on eligible US orders 🩵 read our full return/exchange policy here.

size chart

important info for when you get your onewith ‼️

this is swimwear unlike anything else on the market, so with that, it has some special instructions to truly get a fit that's onewith your body ✨ 'warming up your onewith’ (aka giving the garment a stretch) is MISSION-CRITICAL to the fits-like-undies vibe. your swim actually SHOULD dig in a bit to start if it’s your proper size. then, with a stretch at the openings, it should fit and feel smooth, like a second skin (and/or your fave seamless undies) 🫧

  • proper swim size after stretching

  • proper swim size after stretching

  • swim that is too small after stretching

  • swim that is simply too large in general

size chart notes

remember: you're a human being, and bodies are so much more dynamic than just numbers on a size chart. DM us if you want further guidance on best size!

NOTE: Do NOT expect our suits to be IDENTICAL to no-show underwear in fit. Do note that our suits do not have the same amount of stretchiness of standard no-show panty due to the inner grip strip & bonding.

looking for cup sizes? We don't size by cup! Go with the measurement of the fullest part of your bust, and reference the Bust section of the chart. Or, shortcut alert 📣 order the same size you would for a camisole/tight tank!

"can I just order a few sizes and styles and return what doesn't fit???"

please don't 🫠🫠🫠🫠 read about high volume returns here. (hint: we charge additional return fees for this! it's not great for our small business, the environment, and other customers ☹️)

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