I bought two of these swim shirts, one in purple and one blue. They fit exactly the same. I got an XL because that's the size I wear in a women's shirt and fits perfect. Not too tight not too loose. I wear a bikini top underneath because otherwise you can see uh, you know.. It's not a thin material at all but you can still see stuff. At least with me. The reason it took me so long to review is that I bought these for a cruise out of Florida the end of 2017 and their happen to be a hurricane on my departure date and the cruise was cancelled and never rescheduled. My family just got a pool and used the swim shirts the last few days. I have a sun allergy (Solar urticaria) So I have to stay covered most of the time and this shirt did just that. The only thing that saw the sun was my finger tips and they are blister burnt. The rest not even a hint of color. So I highly recommend these shirts. I also bought some swim shorts that were just as covering, only got blister burnt from the bottom of the shorts down. But I don't recommend the shorts at all because once wet they are hard to remove and pull back up, say for a bathroom break. There is NO WAY of getting them back on until they are dry again. Luckily I bought 2 pair of them.