I don't know how it is from your side, but for me, I've avoided swimming for much of my life, even when I was portrayed as a guy, always afraid to show my bare chest that most of the time if on the beach I'd be wearing a tee shirt, and avoided pools completely, but this mostly because of the chemicals, too strong. But anyway, last year my nephew's family put a pool up in their yard, I went swimming in it, sure I can't wear what I'd really like to wear, package below that would stick out or try to no matter how I bound it up, but I wore a sports bra and shorts (since I didn't have any kind of bathing suit), worked well for me, I felt comfortable enough, but then I wasn't swimming in the general public either. My mom was like, I didn't know you knew how to swim, I told her that just because I've alway avoided going in the water doesn't mean I'm scared of it or that I'm incapable of swimming, she was surprised, sure I'm not a strong swimmer but I'm not going to drown. Anyway, always some way around our wrong parts betraying us, even when going swimming. I know its gotta be a lot harder for FtM to pull it off, because I've rarely ever seen guys going swimming with all their clothes on, top is usually off, guess that won't work too well if you got boobs.