It's So NaturalSwimming naked is just the most natural thing in the world. Why would anyone want to go swimming in clothes that you have to dry off afterwards? If "modesty" is an issue, your body is largely obscured from sight when you get in the water.
When I was sixteen, I was fooling around with friends at someone's house. For reasons that now escape me, my friends had determined to throw me and another girl in the swimming pool. We had the "option" of going in fully clothed, or stripping down to our underwear. As we were both wearing school uniform, the former was not a wise choice, so we both started to undress. However, whereas the other girl stopped at her bra and knickers, I was not keen on the idea of having wet underwear for the rest of the day and so I took everything off! This caused a bit of a stir among the others who were now no longer so keen to lay hands on me, so I jumped in the pool of my own accord and spent a lovely ten minutes splashing about in my birthday suit. When I got out, nobody offered me a towel, so I just wandered around in the nude until I was dry enough to put my clothes back on. Because I didn't make a big fuss about it, or try to cover myself up (which would have been rather futile), nobody seemed to consider it too big a deal and I didn't get any mean commnents directed at me. Conversely, the other girl's underwear went completely see through when she got out of the water and very little was left to the imagination. So her attempts to preserve her "modesty" were in vain and she had the additional invonvenience of having to deal with wet knickers!