I bought these in a 3T for my son for an upcoming beach vacation.  He will turn 3 this month, and he wears a 3T in everything else.  Sadly, these shorts are HUGE, they fall right off him even when tied as tight as possible.  They are so big that I don't think he'll grow into them this year...MAYBE by the end of the summer they will fit.  Thankfully, we have a pool in our backyard so we'll definitely get some use out of them even if it's not til next year.  They are still really cute though, love the vibrant colors and that they aren't "baby-ish" looking.  I plan to order them in a 2T to see if that fits him better.