This dress is gorgeous! The photo doesn't do it justice. It's light, fkowy, and very fairy like. I love that the length of the skit part is perfectly fitting above my hips, which makes me look tall and have long legs.
I'm 5'6 and 114 lbs, ordered a small, a bit loose but I like the loose style on this one.

The material is very soft and thin though, if you mind showing traces of underwater you might want to wear something underneath.