Ditch merchandised character themes for this fun Under The Sea party plan. It’s designed for your child to help craft and DIY their own party! Ages 3–10.

Zara Harper

You’ve set a date, invites have been sent, and anticipation is building for the big event. While you grapple with where another year went your child is bursting with excitement about their party. This party plan caters to ages three through to ten and it’s designed for the kids to craft with you. Letting your child help DIY their party decorations is great for both of you. You have a décor buddy which means no more evenings (aka you-time) spent on secret papier-mâché, while your little one will love crafting with you. They’ll also learn a lot, and on the big day they can show their party guests how clever they are.

Party Plan // Kids Birthday Under The Sea on OccasionLab.com

Danielle Macinnes

One: Choose a theme

This Under The Sea theme is designed to get the kids involved, so apply these ideas to their favourite theme. If your child loves monkeys create a jungle party by switching everything blue to green. Change waves to clouds and switch kelp for trees. Then watch their faces light up when their party is revealed and they see the decorations they helped craft.

Pro Tip: Keep your theme general. Perhaps your child’s a Nemo fan. You could inflate orange balloons and purchase single-use branded partyware. Or you could host an Under The Sea party. Nemo’s still attending but your decorations, food, and game options have increased tenfold! Broader options mean easier, cheaper, and more sustainable party planning for you.

Instead of purchasing one-off character-specific party ware, opt for reusable options. With a dash of creativity cups and plates can be temporarily themed then reused for picnics, play dates, and partyware in the years to come. This option saves you money tomorrow while reducing landfill today.

Party Plan // Kids Birthday Under The Sea on OccasionLab.com

Randall Ruiz

Two: Style the party

This is where your child will shine! Host a crafternoon with their friends in the month before the party. The kids might know all about Nemo’s friends, but what other sea creatures can they learn about while creating party décor?

Materials: It’s a good idea to read the full Party Plan before buying any materials. In most cases items you already have at home will work.

Blue sheet (or green for a Jungle Party)


Cardboard (old packing boxes are perfect)

Paper or newspaper

Sea creature figurines


Potted succulents



String or nylon

Party Plan // Kids Birthday Under The Sea on OccasionLab.com

Raw Pixel

A large backdrop behind your party food table will anchor the scene. Start with a horizontal blue sheet. Help your child create foamy waves across the top of the sheet using white paint handprints. It helps to draw an outline of the wave shapes first. If you have a toddler, read an ocean book and point out the foamy waves beforehand. Next use thick cardboard to cut giant kelp shapes at different heights. Paint each piece a different shade of green. Line up the bottom of your kelp with the bottom of your sheet and attach them with some overlapping for three-dimensional effect. Now’s a good time to hang the sheet behind your party food table (either against your wall or over a portable clothing rail). Feeling creative? Cut out and paint sea anemone, crabs, and coral shapes to attach to your sheet at table height. Scatter stones and succulents across your table so that the cake and party food will appear to be sitting on the ocean floor. Insert all sea food puns here!

Let’s add a game element to finish the backdrop project. You’re busy, so anything that you put effort into should be multipurpose. Buy a tub of sea animal figurines and hang them amidst the kelp. If the table and backdrop weren’t feeling 3D enough, they will be now. Lightly tape string or nylon to the figurines so that they stay attached but kids can pull them off easily when the time is right (more on this game below in step three).

For a truly oceanic vibe hang string or streamers from the ceiling to create jellyfish tentacles for your guests to walk through. Lastly, cut out pairs of ocean dwellers to attach to each cup and plate. Young guests can match their dolphin plate to their dolphin cup when they can’t remember which is theirs.

Party Plan // Kids Birthday Under The Sea on OccasionLab.com

Matt Briney

Three: Dream up some games (kidding, we’ve done it for you)

If you’re resisting the questionable ‘my party was flashier than yours’ fad, good for you. Couture outfits and imported cheeses don’t make a child’s party. The trick to throwing a special and memorable kids party is… drumroll please… games! That’s right, kids love playing games. They also remember games. At show and tell on Monday it’ll be “At Harley’s birthday party I played a really fun game and I won this fish. This is how you play it…”.

Centre the games around each child’s favourite ocean dwelling creature. Mini-charades will have each kid behaving and sounding like their animal while the others guess what they are. Once their animal is guessed they choose a figurine from the cake table backdrop and take it home with them as a party favour. Older kids can silently choose an animal from the backdrop and answer “Does it…?” questions from the guests until the guests correctly guess their animal. What’s this, a triple-purpose DIY? It sure is. Backdrop, game, and party favour all in one.

Party Plan // Kids Birthday Under The Sea on OccasionLab.com

Jakob Owens

If your party is full of creative kids a craft table will let them make their own party favours. Straws, ribbon, newspaper, skewers, and anything else you have around the house will keep them occupied making their favourite ocean dweller mask. A game of Sim Says is brilliant with masks because the kids feel almost invisible in their masks. The kids sneak up on Sim then freeze when Sim spins around. Sim yells “Shark! Crab! Jellyfish! I saw you move!” and they’re out. The first sneaker to reach Sim wins.

When the kids are buzzing with party energy a masked obstacle race is a great option. Set up a themed obstacle course with your child in advance. A plank of wood becomes driftwood over a blue sheet. Green streamers dangling from monkey bars become seaweed. Old tyres can be painted orange, have eyes painted on, and cardboard pincers. Younger kids can jump over the tyre crabs and older kids can push them along the ground to the finish line. The winner gets a sea themed prize. If your group of kids have varied abilities and disabilities make teams of two or three with the goal of working together (like Dory and Nemo’s Dad did in Finding Nemo) so that no child is left behind.

Party Plan // Kids Birthday Under The Sea on OccasionLab.com

Sime Basioli

Four: Prepare the food

Here are some easy Under The Sea themed treats to give your party kids lasting energy to burn. Halve a kiwifruit, stick a toothpick in each centre, and tape paper triangles to the toothpicks for kiwifruit sailboats. Your child can cut the triangles and mark each sail with the first letter of a guest’s name. Personalised sails! Grape skewers become seaweed while crushed popcorn over mashed blue jelly becomes a rough ocean of waves. Position your kiwifruit boats on the ocean between the grape skewers and you’ll have a stormy sea scene.

Cut a shark mouth shape into a watermelon. Scoop out and freeze the pulp. Cut teeth into the watermelon around the mouth you’ve created and attached blueberries for the eyes. Blend up the frozen watermelon pulp with an orange, an apple, and soda water. Pour the mixture back into the shark-melon and serve with small cups. The kids will love putting their hand in the shark mouth to scoop out the slushy drink.

Party Plan // Kids Birthday Under The Sea on OccasionLab.com

Brooke Lark

Five: Relax and enjoy

That’s it! Your easy guide to an Under The Sea birthday party. Or jungle party, airport party, castle party. This party plan is easily adapted to any theme. It’s always a good idea to get the kids involved creatively and in the kitchen. They’ll love making DIY décor and will learn a lot from the experience. Don’t forget to disassemble your party afterward and reuse the materials. The kids could stage a play with the backdrop, while plates and cups can be stripped of decoration before their next use. Happy creating!


Header Photography: Danielle Macinnes


Join Us

New- On the Day You Were Born, personalized book from ISeeMe

Recent Articles