I have used this for triathlons. I bought an XL-I am a size 12 on top and a 36DD chest. I also wanted it to be long enough to cover my whole torso. It fit well, very slim but not skin tight, but the arm holes are quite large and the shelf bra is not super supportive, I still needed to wear another bra. It is long enough to cover the top of my shorts. It is well made and dried quickly.