Most swimwear is designed around a B or C cup sample size. The pattern is graded up from there, which means a size 14 top in a D cup is often just a scaled-up B cup pattern, not a redesigned one. The result is cups that gap at the top, straps that pull forward, and underwires that sit on breast tissue instead of below it. If this sounds familiar, the problem is the pattern, not your body.
Why graded sizing doesn't work for larger cups ¶
Grading a pattern means scaling every measurement proportionally. For a small cup increase, this works reasonably well. For a significant cup increase, it doesn't, because the relationship between cup volume, cup height, and underwire length is not linear. A G cup needs a different seam placement, a different wire length, and a different strap attachment point than a B cup. Scaling a B cup pattern to G produces a shape that holds volume but distributes it incorrectly.
What to measure before you buy ¶
You need three measurements: bust (at the fullest point, bra on), underbust (directly under the bust, snug but not tight), and the difference between the two. The difference in centimetres maps to cup size in most European sizing systems. For swimwear specifically, also measure your torso length from shoulder to underbust, because a short torso changes where the top sits and how much coverage you need.
Construction details that make a difference ¶
Look for tops with a seamed cup rather than a moulded foam cup. A seamed cup can be shaped to a specific cup volume; a moulded cup is fixed. Underwire should sit flat against the ribcage, not on breast tissue. Boning in a bandeau top (a flat reed, not spiral steel) adds structure without the discomfort of underwire. Wide straps distribute weight more evenly than spaghetti straps for cups above a D.
When to use a custom sizing option ¶
If your cup size and band size don't correspond to a standard size (for example, a 65G or a 70FF), custom sizing is worth the extra lead time. At Nex Core Flow Path, the custom fit option at checkout costs nothing extra and adds ten to fourteen days. You fill in your measurements and fit preferences, and the pattern is adjusted before cutting. It's not a bespoke service, but it's a genuine adjustment, not just a size swap.
Swimwear that fits a fuller cup is not complicated to make. It requires a pattern that was actually designed for that cup volume, not scaled from a smaller one. If you've been adjusting your top all day at the beach, the answer is a different pattern, not a different body.