Pushing
Pushing relay games involve one floating toy for each team. Break the children into teams. To be fair, each team should have the same number of children. If there is an extra child, you can pair him with another child and have them swim together, or have him act as a judge. Place half the children on one side of the pool and the other half on the other side. Choose a floating toy for each team. This might be a ball, rubber duck, or even a plastic jug. Each team should have the same toy or item. At the sound of a buzzer or the word "go", the first child on each team swims to the other side of the pool, pushing the toy with her nose. When she reaches the other side, have the first child on that side push it in back to the first side. Continue until all children have had a turn. The first team to finish wins.
Filling
Divide the children into teams in the same way you did in the pushing game. Give each team a cup. Give each team a bucket to place on one side of the pool. At the sound of a buzzer or the word "go," have the first child on each time swim to the other side with a cup filled with water. At the other side of the pool, pour the cup of water into the bucket. To make it more difficult, implement a rule that competitors cannot refill the cup with water before he dumps it. Instead, he must keep the water in the cup from the beginning to the end.
Passing
Divide the children into teams. This time, instead of lining them on each side of the pool, each team stands in a line. Each child should stand behind another, all facing the other side of the pool . Give each team one toy or item. It should be fairly small, like a rubber duck or ball. You could consider a medicine ball, if you want to give the children a workout. At the sound of a buzzer or the word "go," have the child in the front of the line pass the item to the child behind him. When the last child receives the item, he swims with it to the front of the line. Continue until one team reaches the other side of the pool or one team returns to its original order.