I ordered a LG in this (normally wear sz 8), because I didn't want it to be too tight (which I tend to find most rashguards are for me). It feels great. One thing I would mention that I didn't realize when ordering--this has a built in shelf bra. I had planned to wear this over a swimsuit and still can, but the shelf bra also means I can wear this without a swimsuit. So while I at first wasn't sure I liked the shelf bra, it has turned out to be a bonus. Also, for some reason on my home computer the color of the sleeves looked teal/turquoise, the sleeves are definitely a green (kind of kelly green). Love, love the sleeve length!!! This sleeve has been very hard to find, but is perfect.