I bought 3T for my 21 months old son who weighs about 27 lbs.  I think it is true to size, but if you want to make it useful a bit longer, you'd better chose one size larger.  It is a little baggy right now, but looks alright.  Both my son and I love it!

It doesn't keep my godson warm enough although he doesn't shake as much in the pool.  Its still a good product.

This was a high quality wetsuit at a great price.  I bought it for my grandson who is taking swimming lessons and got cold quite often.  This suit fits well, looks great and keeps him warm; he won't go to the pool without it!

Nice design and good quality, but be careful with its size! I bought one in size of 6/6X for my 4 1/2 year old son (120cm tall)  but still feel too tight in length.  Guess size 7/8 will fit better.

I kept reading about it being too small, so I looked at the lbs inthe size chart, the one I bought is from 45lbs and up, my son is 40 lbs so I bought it in case it ran too small.  it feels great, it is a little baggy now, but we put on a couple of extra pounds it will fit great.  My 4 year old son loves it. and it was a whole cheaper here then all the places I researched.

My son is 22 months and average height/weight for his age.  I listened to the other comments and ordered one size up.  3T fits him perfectly.  He's only had a couple of swim lessons, but so far, so good.  Easy to get him into and out of the suit.  He seems to shiver less than the other kids in his class who only wear swim trunks.  Overall, we are very happy with this purchase.