I bought a large cause I swim a lot outside & wanted protection from the sun. I’m 5’5 & 128 lbs & it’s perfect - snug, just so u get an idea. I thought it would run small. Love the cups for coverage & comfort cause I don’t wear bras anymore. Wear it with my bottom or the bottom would be too large. The bottom has little coverage if I did were it FYI.This was extremely cute and what I was looking for, I put the top on and I felt like a freaking giant, the FULL sleeve is like a HALF sleeve. I’m kind of upset, like who wants a half arm tan ??? I wanted full cover like it statesi got a size small and it fit me like an xxs. the sleeve didn't even go all the way down to my wrist. if you're going to spend $30+ on swimwear, go buy a nice one at like a department store or mall. sports stores like academy have rashguards that are way better than this one. you can literally get a brand name (roxy) rash guard for the same price. this swimsuit was absolute garbo. i got shein quality for pacsun prices.Great material. SEXY. Beautiful vibrant color.