So far, she's only worn this in the sprinkler, not the pool. But it doesn't seem to sag at the bum or constrict in the arms or armpits. The pink stripes are adorable and the zip makes it easy to get off for toilet trips and back on again. The sleeves have thumb holes, which 6 y.o. loves! She is a tall 6, usually in a 6x with waists pulled tight. About 52 inches and 52 lbs. The 6 fits perfectly without major stretch.The only possible downside is the cut pf the bum. Not the most conservative cut bSee full review