Twisted Relay Races
Put a twist on typical relay races by adding new challenges. Have kids push an empty plastic bottle with their feet, swim backwards every other lap, walk on their hands or do somersaults in the water between laps. Ask kids to come up with their own ideas, or have the winner of the race pick the twist for the next race.
Red Rover Twist
Have all the kids but one gather on one side of the pool. The final player is the shark, who stands with his back to the others in the middle of the pool calling out other players' names. When a name is called, that person swims to the other side as quietly as possible. The shark tries to catch any player he hears or feels before she can reach the other side. If someone is caught, she becomes the next shark.
Giant Octopus
Choose one person to stand in the middle of the pool and be the octopus. Everyone else lines up on one side of the pool and tries to swim to the other side while the octopus tries to tag as many as she can. Those tagged join hands with the person who tagged them. For the next round, the giant octopus --- all those holding hands ---must try to tag as many others as possible while their hands stay joined. Keep playing until all players have been tagged.
Watermelon Push
Place a watermelon on the bottom of the pool. Kids, as a group, try to push the watermelon to the other side of the pool floor without their feet touching the bottom. Also try this as a race with two watermelons. If someone's feet touch the bottom, he is out.
Avoid the Piranha
Place a ball in the middle of the pool to act as the piranha. Players circle around the ball and join hands. They need to avoid the piranha; if it bumps into a player, he's out. A player can blow on the ball or use the momentum of the water to bump other players with the ball, without touching it himself, but letting the ball out of the circle is not allowed.
Balloon Grab
Inflate about a dozen balloons. Place them in the shallow end of a pool. In 30 seconds, players need to grab and hold onto more balloons than their opponents. Balloons held under their bodies are fair game, but popped balloons don't count toward their totals.