I really like this swimsuit for my granddaughter. At first we tried the 4t for our 4yr old, but the bottoms were very tight on her legs. She is smaller than most kids her age.
We reordered and went with 5t. The bottoms fit great, but the top is really long. This is our first purchase of Ruffle Butts so I'm assuming it's supposed to be that way.
We haven't used it yet so will update when we do.
Updated review: I'm in love with this swimsuit!  I  didn't understand  why the shirt was long, but totally get it now.  I will definitely purchase this swimsuit every summer.