You finally got your bra size figured out. You stopped dealing with bands that ride up and cups that runneth over, and you found brands you can actually trust. Then summer hits, and the swim section is suddenly all small, medium, and large again. Frustrating, right?
Here’s the good news: if you already know your bra size, you’ve done most of the hard work. The swim brands we carry like Freya, Panache, Elomi, Fantasie, Comexim, Anita, and Miraclesuit, use the same band-and-cup system you already know and trust. You don’t have to start from scratch.
Your bra size is doing most of the work
Generic swim sizing assumes everybody, and every body, is proportional. That a bigger bust automatically means a bigger overall size. That isn’t how real bodies work. A 32E and a 38C have the same cup volume on paper, but they have completely different bands, shoulder widths, and torso lengths. Generic sizing tries to squeeze them both into the same “medium” and hopes for the best.
Bra-sized swimwear treats your bust independently from the rest of your body, the same way a correctly-fitted bra does.
That’s why we carry the brands we do. Freya, Panache, Elomi, Fantasie, Comexim, Anita, and Miraclesuit all design swimwear with real bra-style construction: underwires shaped for fuller busts, side-sling support panels, adjustable straps, and band sizing that runs from 28 to 44 (with sizes going well into J cup and beyond). These brands understand that a swimsuit isn’t just a bathing version of a tank top but instead is a foundation garment that happens to be made for water.
If you’ve already put in the work to find bras that fit, the same logic applies here.
What actually changes when you go from bra to swim
A swimsuit and a bra are built on the same basic architecture, but three things work a little differently in the water.
Underwire shape. Swim underwires often have a slightly softer curve than bra underwires. The wire may sit a touch differently against your ribcage. Think of it like the difference between a dress shoe and a beach sandal. Both are made for the same foot but built for different conditions.
Strap construction. Swim straps are usually wider, more durable, and slightly less stretchy than bra straps. They feel different on your shoulders, and adjustment matters more because elastic behaves differently when wet. Tighten your swim straps a little more than your bra straps, then check them after your first time in the water.
Closures and back adjustability. Most bikini tops fasten with plastic clasps at the back. One-pieces usually do the same, while tankinis often have hook-and-eye closures like a bra. The key difference is that most swim closures only offer one hooking position, unlike the multiple rows on a typical bra band. Getting your starting size right matters more here since you can’t easily adjust your way to a better fit the way you can with an everyday bra.
Translating your bra size to swim size
Here are the practical rules we use most often. Read through them, then double-check the specific brand sizing chart for the style you’re considering.
- Start with your correctly fitted bra size. A UK 34G in bras is a UK 34G in swimwear from the UK brands we carry. Begin with the size you already know fits well. This approach will likely result in swimwear that also fits well. Swimwear isn’t an everyday support garment, however, so you have a little more flexibility here than you do with regular bras. If you find a style you love that isn’t available in your size, sister sizing (one size up in the band and one or two sizes up in the cup) is usually worth trying.
- Most of our brands run true to size in the band. The main exception is if you’re between two band sizes. In that case, lean toward the smaller band. Since swim tops typically have fixed clasps with little to no adjustability, starting with the snugger band helps maintain support and prevents the top from stretching out too quickly over time.
- Your cup size usually translates directly — with one important note. The shape of the cup can vary depending on the style. A balcony top and a plunge top offer different support, shaping, and levels of coverage. Therefore, you might need to choose a larger cup size for plunge styles to ensure the best fit and coverage.
- Bra-sized versus alpha-sized swimwear. When shopping for alpha-sized swimwear (sized by dress size or in S/M/L), choose the size that matches your usual dress size or the size you wear in a fitted t-shirt. Bra-sized tankinis and one-pieces, however, are usually designed with an average or slightly shorter torso. If you have a longer torso, fuller hips, or a fuller stomach, we recommend sizing up one band size. This gives you extra length and room through the torso without changing the cup fit. We suggest this tip often, especially for tankinis you want to layer over a high-waisted brief or for taller customers who need more length or coverage in a one-piece.
- Swim bottoms (which are normally alpha or dress-sized). We usually recommend ordering on the snug side. When the fabric gets wet, it can look and feel saggy if it’s too loose. This is especially helpful if you’re between sizes.
- Bandeau styles fit differently. Bandeau bikini tops rely entirely on the band for support since there are no shoulder straps helping out. Always choose the smallest band possible for bandeau swim tops is often recommended.
Brands run differently, and that’s normal
Even within bra-sized swimwear, no two brands or styles fit exactly the same. The differences are often small, but they can matter if you’re between sizes or trying something new. Here’s a quick guide to the brands we carry most often:
Freya — True to bra size and consistent across styles. Best for petite to medium frames and various breast shapes. Tends to offer lower-cut styles and more youthful colors and prints.
Panache — True to size with a slightly higher center gore and firmer wires. Excellent for a wide range of body frames and breast shapes, though it particularly excels for women with full, heavy breasts. Carries up to a UK K cup and tends to offer more balcony-shaped styles.
Elomi — Very reliable, especially in larger bands. Great for medium to plus-size frames and fuller busts with more side tissue. Offered up to a UK J/JJ and fits similarly to their plunge bras.
Comexim — Uses Polish sizing and runs one to two cups smaller compared to standard UK sizes. The wires are also more flexible. Order one cup size up from your UK size for a pushed-up look, or two cups up for more coverage. Read Melissa's comments for more details. Best for full, projected breasts on smaller to medium frames. Less ideal for very heavy breasts or significant side tissue.
Fantasie — True to size. Best for small to medium frames and busts. Offers good coverage options. We mostly carry their tankinis, with some bikinis available.
The takeaway: The bra-sized system is consistent, but the small refinements vary by brand. If you need help with Comexim or any other brand, just email service@breakoutbras.com. We’re happy to help with any style or brand questions.
When to ask for help
Sizing yourself for the first time can feel overwhelming, and you don’t have to figure it out alone. Our team offers free virtual fittings for swimwear with no pressure to buy. Whether you’re between sizes, trying a new brand, or considering a halter or one-piece for the first time, fifteen minutes with a fitter can make a big difference.
Adjustments after a swimsuit arrives are also normal. If something doesn’t feel quite right, send us a photo or two and we’ll help troubleshoot whether it’s a sizing issue, a style issue, or just straps that need tweaking. Browse the full swimwear collection whenever you’re ready, and reach out if you’d like a little guidance along the way.
Frequently Asked Questions
What is bra-sized swimwear? Bra-sized swimwear uses the same band-and-cup system as traditional bras (28D, 34G, 40H, etc.) instead of generic small/medium/large sizing. This lets you get a proper fit without compromising on the rest of your body. The brands we carry, like Freya, Panache, Elomi, Comexim, and others, use real bra-style construction with underwires, side support, adjustable straps, and bands from 28 to 44.
Do I wear my bra size in swimwear? Yes. A UK 34G bra size corresponds to a UK 34G in swimwear from UK brands such as Freya, Panache, and Elomi. These brands maintain consistent sizing across their bras and swimwear collections. Be sure to check Melissa's comments on each style page for any minor fit differences to consider when purchasing.
How is swim sizing different from regular bra sizing? Swim fabric stretches differently when wet, swim underwires tend to have a slightly softer curve, swim straps are wider and more rugged, and there’s usually less back adjustability than a multi-hook bra band. The basic principles are the same, but the details are adjusted for water and movement.
Should I size up or down in swim? If you find yourself between band sizes, we suggest opting for the smaller band. Swim clasps typically lack adjustability, so starting with a band that is too loose may compromise long-term support. Cup sizes usually correspond directly with your regular bra size; however, you might need to increase the cup size for styles that offer less coverage, such as plunge designs. Tankinis and one-piece swimsuits are often cut slightly shorter in the torso, so if you have a longer torso or a fuller stomach or hip area, choosing a larger band size can provide additional room and comfort.
Can I get a virtual fitting for swimwear? Absolutely! We offer free virtual fittings specifically for swim. This is especially helpful if you’re trying a new brand, you’re between sizes, or you’re considering a halter, bandeau, or one-piece for the first time.