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XS 00-0 32 - 33 24 - 25 35 - 36
S 2-4 34 - 35 26 - 27 37 - 38
M 6-8 36 - 37 28 - 29 39 - 40
L 10-12 38 - 39 30 - 31 41 - 42
XL 14-16 39 - 41 32 - 34 43 - 45
2X 18-20 42 - 44 35 - 37 46 - 49
3X 22-24 45 - 48 38 - 41 50 - 52
4X 26-28 49 - 52 42 - 45 53 - 55


NOTE: Do NOT expect our suits to have as much give as your standard no-show underwear. It's super important to STRETCH your suit before each wear, but do note that our suits do not have the same amount of stretchiness of standard no-show panty due to the inner silicone & bonding. If you are AT ALL in-between sizes, size UP!

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!

Some IRL size reference pics for you:

how does onewith run

plus size flattering swimwear

midsize swimwear

Revised sizing!

We heard you! 📣 We know that our first collection of dig-free swimwear ran small. It was our first collection after all, and we were keen to absorb customer feedback and put it into action with our newest suits! With that, onewith now runs much more true to size. However, to ensure you get that onewith-your-body fit — if you are in-between sizes, be sure to size up to not chance the suit digging in 🥴 and make sure to STRETCH your suit before each and every time you wear it; this 'warms up your onewith' and creates slack in the garment for that optimal, lay-flat look that makes for swimwear that feels like underwear 🌊

⛔ Bracketing is STRONGLY discouraged: while we understand the desire to find your best size, ordering multiple sizes of a piece with the intention of returning those that do not fit creates inventory issues for us as a small business, and also compromises hygiene best practices. While we encourage you to stock up on your fave swim, please do so mindfully for other customers' sake (that is, without the intention of returning extra sizes/styles). While this may be more permissible for an enterprise-level company, we ask that you consider how bracketing affects a small business. Returns of 3 or more pieces/customer will be subject to a separate fee in addition to the return fee: 10% of the full order amount. Orders placed after 1/17/23: orders returned due to multiple sizes ordered will also be subject to the bracketing fee of 10% of the full order amount in addition to the return fee.  

Bellows One Piece Torso Measurements

SIZE INCHES - shoulder to crotch, relaxed
XS 24.25
S 25
M 26.75
L 27.25
XL 28
2X 28.75
3X 30.75
4X 31.25

Torso fit note: For our customers concerned about fit for a long torso: MANY of our models (that we both fit on + do shoots with!) have a long torso. We hear time and time again that our one pieces are amazing for tall women + those with a long torso 📏 we think you'll love the fit!

one with swimsuits that fit like underwear

one with swimsuits size guide

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