"The costume is very cute on the baby shown. I believe it will be super cute on my little guy also, but I am exchanging it right now. I ordered the 18 mo/2T size for my 11 month old boy. He is a big boy so I wanted it large enough to snap and wear something under it. He weighs at least 24 lbs and is pretty tall for his age. I went by the size chart and felt that the 18 month size would be appropriate. I also knew I'd be putting on clothes underneath the costume. It was swimming on him! I am going to exchange it for the next size down (probably where he should be). I just didn't want it to be too small. Other than that, it was pretty cute. I'm excited to see if the other size fits better. It is thin so the kiddos will need to wear clothes underneath it. We'll see how it goes."