I ordered the blue color in size large (2-4yrs) for my tall 30 lb 2 year old that wears usually wears 3T clothes (in Carters brand for reference), some 4T in certain brands. It is a little too big in the diaper area, but with all the ruffles and a water logged diaper, it should fit great. Im glad I ordered the L because the top was slightly narrow and cuts inwards right at chest level. We can pull it up a little higher for more coverage. The adjustable halter is great - easy to custom fit. The material is a swimsuit material, not cotton, as the seller updated in the description. This swimsuit is cute enough to wear as an outfit and functional enough to wear in the pool and splash pad. The print is really pretty in my opinion. The colors in the sellers picture are a great match to what we received. There is 1 long string where they kept sewing a little too long, but it is easily snipped off and fixed. It is still cold where we live so my diva daughter hasn't worn this swimming yet, but she does like to put it on and practice the model walk her grandma taught her.