Have the kids play the “Wet Shirt” relay, an idea from www.clean-pool-and-spa.com. The game is simple — have two teams line up on the same side of the pool with player number one wearing a large t-shirt.
1. Player 1 jumps in and swims from one side of the pool and back, jumps out and takes the wet shirt off and player 2 then puts it on.
2. Player 2 jumps in and swims from one side of the pool and back and so on.
3. The first team done WINS!
To make a varying degree of difficulty, add things like goggles, snorkels and swimming fins.