My daughter is 8 and has a very thin build. It is hard to find swim bottoms that fit in the waist and that stay in place under the butt. These swim bottoms fit perfectly. The waist band is thick enough to help fit snugly around the waist, but not too thick that it squeezes or is uncomfortable. The same goes for the leg holes that it fits snugly but not too tight. These are the best fitting bikini style swim bottoms I have ever found for her. Although she has a thin build, I do think these would work great for other body builds too-just pay attention to sizing measurements. These fit true to size. So glad to have found these and will be ordering more.