Find the Bottle
Try this team-building game in the pool. Remove the wrapper from a 20 oz. soda bottle and fill the bottle with water. Divide the players into two equal teams. Send the teams to opposite sides of the pool and have them get in. The players turn away from the pool while you toss the bottle into the middle of the pool.
When you say "Go," the players work with their teammates to locate the soda bottle before the opposing players. The goal is to carry the bottle to the opponents' side to score a point for your team. Because you can't see the bottle very well underwater, players can try to sneak the bottle past their opponents and hand it off to their teammates whenever necessary. The first team to get to 10 points wins the game.
Follow the Swimmer
Pick one person to become the leader and have everyone get into the pool. Players line up single-file behind the leader. The leader then performs a movement that the followers have to mimic. The leader can, for instance, perform a backstroke motion, doggie-paddle or even just float. The followers have to learn from the leader any move he makes and ask their teammates if they have questions about a particular move.
Once the leader has had some time in the pool, assign the second person in line to the leader position and start again. Do this until everyone has had a chance at playing the leader.
Rafters' Relay
Divide the players into two teams and line the teams up at one end of the pool. Have one player from each group stand at the other side of the pool. She holds one end of a rope that stretches across the pool to her teammates. Place a raft in the pool in front of each team. The two first players in both teams get into the rafts.
When you say "Go," the players hold the rope and pull themselves across the pool. When each gets there, she gets out and holds the rope, and the player she displaces makes her way back to her team. The first player becomes the new rope-holder while the second player in line has her turn on the raft. The first team to have all its players in their original positions wins the game.