15 Under the Sea Birthday Party Ideas That Kids Will Love!

Plan a world of wonder for your kid with an under the sea birthday party! From glittering mermaids to playful sea creatures, this party theme offers endless fun for young adventurers. Here are 15 exciting ideas to help you party plan the ultimate underwater celebration.

1. Under The Sea Piñata

A piñata shaped like a shark, treasure chest, or sea turtle is a surefire crowd-pleaser. Fill it with candy, small toys, and ocean-themed trinkets for a fun activity that doubles as a party highlight.

2. Ocean-Themed Temporary Tattoos

Kids love temporary tattoos, and ocean-themed designs like starfish, jellyfish, and sharks are a hit! Set up a tattoo station where kids can choose and apply their favorite designs to get party-ready.

3. Face Painting with Ocean Designs

Add a splash of color with face painting! Offer designs like mermaid scales, fish, starfish, or even whimsical bubbles. Hire a professional artist or set up a DIY station with safe, washable paints.

4. Sea Creature Ceramic Painting

Provide unpainted ceramic figures of sea creatures like fish, octopuses, or crabs, along with paint supplies. This creative activity lets kids decorate their own under the sea birthday party keepsakes while diving into their imaginations and getting creative.

5. Under the Sea Invitations

Set the tone with themed invitations that feature sea creatures like dolphins, turtles, and whales. I’ve made a couple different under the sea birthday party invitations that all feature editable text and can be easily edited right inside your web browser. Be sure to check out the end of the article if you’re interested in my designs.

6. Themed Cupcakes

Serve cupcakes decorated with ocean-inspired elements like whales, fondant waves, or edible glitter. Display them on a tiered tray for an elegant touch, and make them a centerpiece of your dessert table.

7. DIY Seashell Necklaces

Create a craft station where kids can attach seashells to strings or chains to make their own necklaces. This doubles as a fun activity and a memorable party favor. To make it even more unique you can have the kids find their own seashells if you’re hosting the party near a beach!

8. “Dive for Treasure” Game

Fill a kiddie pool or large container with water and toss in small toys, coins, or plastic gems. Provide nets or scoopers for kids to “dive” and collect their pirate treasures.

9. Ocean Life Balloons

Under the sea birthday party balloons are a great way to playfully add to the theme. Designs like starfish, sharks or just an assortment or light blue and white balloons can help transform the party space.

10. Homemade Cookie Craft

Bake plain sugar cookies in the shapes of fish, seashells, or starfish. Set up a decorating station with icing, sprinkles, and edible glitter so kids can design their own edible masterpieces.

11. Bubble Play Station

Set up a bubble station with wands and bubble machines. Kids can chase and pop bubbles, adding a playful underwater effect to your outdoor space. Get large bubble wands ahead of time and turn this into a big bubble competition for the kids. Be sure to have a camera nearby!

12. Ocean-Inspired Cake

A show-stopping cake is a must! A simple blue and white frosted cake with ocean themed toppers is great, but be sure to check if your local baker can help out to make a truly unique cake design. Some of my favorite childhood photos are one’s where I’m posing with my birthday cake. A creative cake can help make birthday memories really special! 🙂

13. Ocean Storytime

Designate a cozy area for storytime with books about the ocean or sea creatures. Stories like The Rainbow Fish or Commotion in the Ocean will captivate younger guests.

14. Ocean Slime

Make or buy ocean-themed slime in shades of blue and green with glitter and tiny sea creature toys mixed in. Set up a slime station where kids can squish and stretch their creations, or provide small containers so they can take some home as a party favor.

15. Nautical Party Favors

Send guests home with bags filled with under the sea birthday party goodies like stickers, mini puzzles, and bubble kits. Add a personal touch by including a thank-you tag that says, “Thanks for diving into my party!”

Bring Your Under the Sea Party to Life With Our Printables!

Planning an under the sea birthday party is easier with our collection of printable decorations and party supplies. From invitations to cupcake toppers and birthday banners, our designs can help add a magical touch to your event. Customize them easily in your web browser and make your child’s special day unforgettable! Check out our selection of under the sea birthday party supplies to dive into stress-free planning. Every design comes with a free demo version you can test out before buying.