I will always wear board shorts with my suit, whether it is a one-piece or two-piece, if I am at a water park. The water slides will sometimes move the bottom piece around, and I don't want to show too much. I feel more comfortable wearing shorts with my suit.
I would say that the people do it mostly for modesty. They are not comfortable showing as much, or feel iffy about that area.
hide their tummy
to cover up more and it might be uncomfortable walking around with a little buldge
When I'm having fun: To cover up areas I don't like.
For swim practice: To create drag.
For swim meets: Just something to have on while I'm waiting.
So they dont have to wax.
DUH.
To cover up more than they want to show.
to cover their butts
Everything has to end one day...
Let's make a petition to abolish swimming suits...
We might sometimes have to look the other way, but overall, I think it will be OK...
some just like to have even more coverage than a one piece gives
Mostly, it's to cover up more skin...But, I know that I wear shorts over my one-piece at a swim meet (I'm a competition swimmer).