17 Mermaid Birthday Party Ideas for Underwater Enchantment

Published December 10, 2021
Mermaid party decoration and cake

If you are planning a mermaid birthday party for your ocean-loving child, these fantastic ideas will help you plan, organize and throw the most memorable under the sea experience for the kids.

Clamshell Cookies

DIY Clamshell cookies

These do-it-yourself clamshell cookies will make all your sweet mermaid wishes come true. You can create these under the sea inspired cookies at home in no time using plain store bought sugar cookies, buttercream, and candy pearls. For a fun presentation, display them on a dessert stand complete with graham cracker crumbs to mimic beach sand.

Under the Sea Balloon Garland

Transport the kids to an under the sea experience and make a party statement with a dazzling balloon garland complete with under the sea inspired foil balloons and these spectacular transparent floating bubble streamers added to mix. It makes the perfect festive backdrop for a mermaid themed party as it can instantly transform any space.

Jellyfish Lanterns

These DIY jellyfish party decorations are easy and inexpensive yet they add an amazing eye-catching detail to any celebration. Make these party decorations in coordinating colors to match your event and hang them from the ceiling. All you need is paper lanterns and tissue paper.

Mermaid Tail Cupcakes

Mermaid cupcakes

Spruce up simple cupcakes with sprinkles and chocolate mermaid tails. If you have a mold you can get creative and make your own chocolate tails or simply purchase the cupcake decorations online.

Under the Sea Party Invitation

Selecting a one of a kind invitation design sets the tone to your event and allows guests to know what to expect. For a Mermaid theme, consider a colorful and sparkly design which will help you decide on other details of the party, such as decorations, outfits for the birthday child, tableware, and party menu.

Mermaid Tableware

Mermaid or under the sea themed plates, cups and napkins are party essentials that will establish the theme and get the kids excited to join the other guests around the table.

Under the Sea Decorated Cookies

Homemade gingerbread cookies in the shape of octopus, shell, jellyfish, starfish, seahorse and whale

No party is complete without decorated sugar cookies to match the themes. If decorating cookies is not your cup of tea, order cookies from a cookie designer and request them to perfectly match your invitation design.

Mermaid Bingo

A fun and adorable Mermaid Bingo game is a perfect touch to bring a little extra fun to any birthday party celebration. Give each player a bingo card and markers (small sea shells). Have each player put a marker over the free space. The caller will draw a calling card and announce the item. Each player will cover that item on their card with a marker. The first player to make a line of five items (diagonal, horizontal or vertical) yells out BINGO and wins the game! If you need help downloading, use this Guide for Adobe Printables.

Mermaid Party Favors

There's plenty of wonderful ideas for mermaid party favors ranging from personalized beach pails to sequin mermaid tail pouches you can fill up with under the sea goodies for your guests to take home. Choose an idea that fits your budget but doesn't lack creativity.

Under the Sea Cake

Mermaid theme cake

Whether you are hosting a big bash or a more intimate celebration, a birthday cake is essential to complete your tablescape. You can opt for an intricate fondant mermaid cake design or make your own buttercream cake and decorate it with mermaid inspired embellishments, such as edible under the sea cake toppers.

Mermaid Inspired Candy Station

Mermaid macarons and cookies in pink and turquoise colors

Fill up separate clear bowls with an assortment of under the sea chocolate bites, candy pearls and gummies to create a fun candy station bar for the kids. Make scoops, clear bags, or paper treat cups available for the guests to treat themselves.

Crab Croissant Sandwiches

Ideally, tuna salad would be the best choice for these crab croissant sandwiches to match the under the sea theme. However, you can create using what appeals to your guests the most. Among kids' favorites are ham and cheese and peanut butter and jelly.

Mermaid Bath Bomb Party Favors

Making bath fizz bombs at home concept

These mermaid bath bombs will make your little mermaid squeal with delight and take bath time to the next level. If making bath bombs doesn't intimidate you, create mermaid inspired bath bombs from scratch. If you think it's a big project to take on, you can easily purchase bath bombs online to match your event.

Ocean Blue Punch

Keep the little guests hydrated with a refreshing ocean blue punch complete with Swedish fish or any other under the sea gummies you may find at your local candy store.

Quick recipe: Mix one gallon of your favorite blue punch with two liters of lemon-lime soda. Have fun straws, ice cubes, Swedish fish or other fun gummies available to complement the drinks.

Jellyfish Ornament Craft

Jellyfish Craft Ornament

Using upcycled egg cartons, the kids can create their own adorable jellyfish ornaments.


  • Egg cartons
  • Metallic acrylic paint
  • Paint brushes
  • Glitter
  • Googly eyes
  • Ribbon (a variety of sizes and style)
  • Bead necklaces, optional
  • Mini rubber bands
  • Scissors
  • Craft glue
  • Hot glue


  1. Cut out individual egg carton cups. Paint them in the pretty colors and add glitter. Allow them to dry.
  2. Use a pair of scissors to poke a hole in the center of the egg carton cup.
  3. Cut a 5" piece of ribbon. Loop it and tie the ends together into a knot. Pull the top of the loop through the hole to make a hanger.
  4. Glue googly eyes to the front of the egg cup.
  5. Cut 12" long ribbons using a variety of sizes and styles. If using, cut the bead necklaces to roughly 12" as well. Use a mini rubber band to hold the ends of 6-10 ribbons and/or bead strings together.
  6. Hot glue the rubber band bundle up into the egg cup jellyfish head. (*Adult supervision required for working with a hot glue gun.)

Mermaid and Pirate Costumes

Guests can dress up in mermaid and pirate costumes and turn the celebration into a magical under the sea costume party. For extra fun, have a few under the sea photo ops available.

Treasure Chest Party Activity

Keep the little mermaids and pirates happy and entertained with an engaging party activity. Grab a treasure chest or a simple cardbox, fill it up with sand, and hide under the sea inspired toys and candies. Print out copies of the treasure card and have your mermaids check the treasure chest (or box) and look for under the sea treasures.

Plan the Mermaid Party of Your Kids' Dreams

Whether you are throwing a mermaid birthday party indoors, by the pool or at the beach, this wonderful theme will give you the creative freedom to incorporate as many as water themed party ideas as you want to throw the mermaid party of your kid's dreams.

17 Mermaid Birthday Party Ideas for Underwater Enchantment