Fits awesome, except that I have to stretch out the neck severely before I try to put it on my 20 month old otherwise there's crying.The neck hole doesn't need to be *that* tight does it. I'm hoping it'll get looser as we use it more, but will hopefully keep it's elasticity.
I ordered this for a very petite and small 2 year old girl and I have a hard time getting it over her head, and she hates putting it on as a result. That's my only real complaint as it fits in length and arms otherwise. We use this to play outside in the water in strong Southeastern US sunshine, which is the main reason I bought it. It doesn't keep her very warm in cold water, so expect to come out for breaks to warm up.
My son is a skinny 5 year old who weighs about 45 pounds. I ordered a 7/8 and it's too short in the arms! Even though he wears a 6 in boys shirts, he needs a 9/10 for this shirt to fit him properly. It's also a pain in the butt to get his head through this shirt, but came off surprisingly easy when it was wet.
This would be good to avoid sunburn, but it wouldn't keep a child warm in a cold pool since it isn't lined. My son complained the arms were too short; he is really thin and long arms.
My 6 year old son loves it and it keeps him warm. I ordered a 9/10 and it fits him just right and he is actually skinny.
Nice, well made shirt. I have a very slim 4 year old and while I did order a size larger, the neck opening is very snug. I may get one year's worth of wear out of it.