Water shoes!!!! Definitely!! Me and DH went barefoot one year until he sliced the bottom of his foot open in the shark reef at TL. Had to go to nurses station to have it cleaned, bandaged, and couldn't swim the rest of the day. Taught us a valuable lesson.
So I say water shoes because you need them even in the water. Obviously, you can't swim in flip flops and would have to take them off in the water and we unfortunately learned that you are just as likely to get hurt in the water as out.
They were really nice though and gave us two free tickets to come back another time (sadly, have no idea where they are now)...