I haven't swam in boxers, but just reminds me of something else that happened. I was at an outdoor concert with friends where it rained heavily the whole time. After the concert me and one of the guys walked back to my house as it was close by, where he was going to call a taxi to take him home. As soon as I got in I said to the other guy sorry but got to get out of these and stripped off my soaking wet cloths, and just left in my boxer briefs. I had white boxer briefs on and they were completely see through - don't think i could go swimming in anything like that.