Sharks & Minnows. In this version of tag, the "shark" hangs out in the middle of the pool while the rest of the "minnows" line up at the end of the pool. The minnows have to successfully swim by the shark without being tagged, or they become the shark for the next round.
Pool Basketball. Basketball doesn't have to happen on dry land. If you want to make it interesting, try this Floating Water Basketball Hoop ($36) instead of using a stationary poolside hoop.
Animal Polo. Like Marco Polo, but with animal sounds! Instead of Marco, the "searcher" calls out an animal name, and the "hiders" call out the animal's sound.
Beach Ball Race. Give each child a beach ball and see who can make it from one side of the pool to the other first while pushing their beach ball along in front of them. Go with a classic Novelty Beach Ball ($9, originally $13) that comes in a 3-pack.
Water Balloon Towel Catch. Each player gets a towel to hold and must use to toss water balloons to the other players, who must catch and throw the balloon with their own towel. Any child who misses their balloon — or breaks one in their towel — is out. The last player standing wins. (This is one better played poolside, since broken balloon bits can mess up a pool's filtration system. Or opt for Reusable Water Bomb Balloons ($36) instead.)
Diving Games. Gather up a bunch of items that sink and throw them into the pool for your kiddo to retrieve. These Torpedo Bandits ($11) glide underwater, and they're so fun to swim after as they sink.
Invisible Water Bottle. Go DIY by filling an empty water bottle without a label and throwing it into the pool while the kids look away. When they hear the splash, they can jump into the pool to look for the camouflaged bottle.
Freeze Tag. Like out-of-water freeze tag, one player is "it," and anyone who gets tagged must freeze in place. Unfrozen players can swim underwater through a frozen player's legs to unfreeze them.
Float or Sink. Play by throwing items into the pool and having your kids count how many items floated and how many sank. You can also have them guess beforehand if an item will sink or float. It's basically a science experiment.
Categories (Pool Edition). One person stands at one end of the pool and chooses a category, such as "colors." The other players huddle to share their color choice with each other, and then the solo player begins calling colors one at a time. If their color gets chosen, they must jump into the pool and try to swim to the other side without the other player catching them.