There’s something magical about throwing a birthday party in the middle of summer—especially when there’s a pool involved. Kids are splashing, sunscreen’s everywhere, someone’s always half-drenched in their clothes, and you just lean into the chaos with a beachy drink and a grin.
But if you’re planning a summer pool party for your little one (or a group of high-energy cousins), having a fun, clear theme can make the whole thing feel intentional—without adding too much stress or cost.
So whether you’re dreaming of a Hawaiian luau, a backyard pirate takeover, or just a sweet blue-themed party with pool floats and cupcakes, here are 15+ pool party themes for kids’ birthdays that are easy to decorate and fun to play in.
Beachy Birthday Bash
Think classic beach birthday party vibes: striped umbrellas, buckets of snacks, seashell garlands, and blue punch with floating gummy rings. Great for big groups and works with minimal prep.
Ocean Friends Theme
Decorate with ocean animals—octopus balloons, jellyfish lanterns, and a few floating toy turtles. Bonus points if the birthday cake looks like it came from under the sea.
Pirate Pool Party
Arrr matey! Set up a treasure chest cooler, hand out pirate hats, and let the kids go on a splashy treasure hunt around the pool. Float some “gold” coins and watch the chaos unfold.
Blue-on-Blue Bash
This one’s all about the aesthetic. From pool floats to cupcakes, towels, balloons, and swimwear—everything in shades of blue. It’s oddly calming and surprisingly cute.
Hawaiian Luau Pool Party
Pass out leis, set up a DIY juice bar, and put on some ukulele music. Add a mini hula competition and a pineapple centerpiece and you’ve got yourself a tropical backyard vibe.
Mermaid Water Party
Tail towels, pearl necklaces, shiny decorations, and a soft ocean-inspired colour palette make this a dream party theme for little mermaid fans. Add a “shell painting” station with water-safe paints.
Shark Attack Theme
Use grey and blue decorations, add shark fins to the cupcakes, and float a giant shark inflatable in the middle of the pool. Add in “rescue the diver” water games for fun.
Mini Olympic Pool Party
Set up little competitions: float races, sponge toss, water balloon dodgeball. Use cones or pool noodles for lanes and let everyone earn a DIY medal at the end.
Ice Cream Pool Party
Float a cooler full of ice cream cones (wrapped or plastic toys), make poolside sundaes, and decorate with sprinkles, pastel balloons, and big scoop signs. No one minds the mess if it’s cold and sweet.
Glow-in-the-Dark Night Swim
Perfect for slightly older kids. Think floating glow sticks, underwater lights, glowing rings, and neon face paint. It’s a party after dark that feels way cooler than it is complicated.
Tropical Fruit Party
Go heavy on pineapples, watermelons, and fruit-shaped floats. Decorate the fence with cut-out fruit garlands and serve fruit punch with reusable cups and mini umbrellas.
Under the Sea Bubble Party
Decorate with hanging bubble garlands (fishing line + clear balloons), use bubble machines, and fill the yard with all things floaty. Even simple bubble wands become magic in the right setup.
Poolside Carnival
Add some old-school fun like ring toss, sponge dunk buckets, or inflatable bowling. Add cotton candy or popcorn and a few prizes, and it feels like a mini fair—just wetter.
Backyard Boat Party
Use inflatable boats instead of floats, hand out “captain” and “first mate” badges, and create a small obstacle course in and around the pool with floating pool noodles.
All-Things-Rainbow Pool Party
Rainbow floaties, rainbow towels, rainbow balloons, and a cake with every colour layered inside. It’s fun, bright, and photogenic for those summer snapshots.
Sweet & Simple Classic Party
No theme, no stress—just streamers, pool noodles, summer snacks, and fun games like duck races, water balloon tosses, and sponge tag. Sometimes simple is the sweet spot.
Final Thoughts
Planning a pool party doesn’t have to mean spending a fortune on themed decorations. Choose a vibe, get a few matching elements (think: towels, tableware, floats), and lean into summer fun. Whether it’s pirates, mermaids, or just inflatable ice cream cones—kids remember the water fights more than the fancy setup.