ebay recommended that I get an "S” size, but when I got it, it was way too small, tight. "M” is more a true size fit. Went swimming in it, it took 40 mins to dry in the sun. Felt like it wasn’t made for swimming. Good for sun protection, light on body, but feels "thicker” than what you might expect for a casual swim in the ocean. This will probably work great for sporting activities.See full review