From my own experience it is best to apply a few times over a few days period initially to get the color going, then re-apply once to twice a wk following. But I am very fair skin (porcelain/light ivory) tone and do not tan well. Someone with darker tone wouldn't need to re-apply as often. As far as the swimming, it would all depend on the mixture You choose to use. Choose Yourself a really good base (as You will see in the directions if You decide to bid and win) and it will hold well :-)