I ordered for my 2 y.o son for an upcoming trip. He's currently wearing 3T but can get away with some 2T items that fit him exactly. He's roughly 30 lbs and just about 3 ft tall. He's not chunky-think an athletic build for a toddler :). I find that this runs slightly small, I ordered a 3t and 4t to see which was best. I kept the 4t and returned the other one, my son is tall for his age but this fit him well. The shorts and rash guard are a bit long but I know after wearing/washing come summertime it'll be fine. The 3t fit him exactly.