Get the removable cups.

Yes, removable cups are exactly what you need. They let you fix asymmetry without sewing or special ordering.

Most swimsuits with sewn-in padding assume your chest is symmetrical. It’s not. The fix is simple: buy a suit with removable cups, then take out the padding from the smaller side (or add a little extra if the suit has pockets). You can even swap cups between brands or buy a second set online. No one will notice except you, and you’ll finally feel comfortable.

Don’t waste time trying to pad the smaller side with silicone inserts or double-sided tape. That stuff shifts in water and looks lumpy. Just use the built-in system.

Your swimsuit should fit you, not the other way around.