Best sunblock for swimming?

Question

I burn pretty easily but I really like to swim.

I'm wanting to take a summer swimming class to fulfill my college requirements but the class goes for about 3 hours and I don't want to climb out of the water every 90 minutes, get completely dry, put on sunblock again and miss about 15 minutes of class.

So it there any sunblock out there that can last longer then 3 hours while in water?

Answer 1

Banana Boat SPF 50

Answer 2

Coppertone!

many different SPF

works sooo well

waterproof