Under the Sea Birthday Party

Ideas for hosting an Under the Sea themed party

Dive in for an under the sea birthday party that’s guaranteed to be a whale of a good time! Find ideas for decorations, invitations, activities, and more.

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Under the Sea Birthday Party Invitations

Set the tone for your party right from the start by sending great invitations. You can either purchase pre-made invites or make your own. Here are some of our favorite invitation ideas for both options:

under the sea birthday party invitations

Use Ocean Theme Decals – This simple fish invitation was made by folding over a piece of blue cardstock and attaching colorful stickers and white paper with the party’s information printed on it. For a finishing touch it had two holes punched in the top and a coordinating ribbon threaded through.

Sea Creature Invitations — Write your party information on an invitationshaped like your favorite sea creature. A fish, a shell, or a starfish are all easy-to-make shapes that become fun backgrounds for your invite. Decorate your shaped invitation using themed stickers or your own artwork. Here are a few ideas for catchy invitation wording:

  • Come for a Whale of a Good Party Sure to Please You Heart and Sole.
  • An Under the Sea Birthday Party — Come Mussel in on the Fun!
  • Dive into the Fun at ____________’s Under the Sea Birthday!
  • You are O’Fishally Invited for a Whale of a Time!


** General Party Invitation Tips ** — If you choose to make your own invitations, don’t forget to include the date, location, and time of your party. It is also helpful to put the host’s name, RSVP by date, and either your phone number or email.

You can always find lots of great online party invitations with a free RSVP manager at Evite,


Here are some invitations that we like, available for purchase from our friends at Shindigz:

Under the Sea Personalized Flat Invitations
Under the Sea Personalized Invites
Sea Friends Personalized Invitations
Sea Friends Invitations
Under the Sea Invitation
Little Fish Invitations


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Under the Sea Decorations

under the sea party decorations

Decorative fishnet is great for an under the sea party theme!
There are lots of great ways to decorate for an under the sea birthday party theme. Use shades of blues and greens, and add accents of either yellow, orange, or purple. Incorporate these colors into your décor by mixing them up in your tableware, and also by using them in things such as balloons and streamers, and you’ll be well on your way to a fishy feel. Here are some other ideas:

  • Stretch blue streamers close together to cover your ceiling, putting an occasional twist here and there in each one. This will look like the ocean is overhead!



  • Replace white light bulbs with blue bulbs for an underwater effect.


  • Tape colored streamers to your balloons to look like octopi legs.


  • Draw on smiley faces with Sharpie marker for a sea of floating octopi!


  • Cover your windows with blue cellophane and attach cut out shapes of sea life to create an underwater look.


  • Make an under the sea birthday party centerpiece by using glass bowls or containers filled with colored water (experiment with different shades of blue and green.)


  • Put sand and small shells in the bottom and floating candles on top.


  • If you have any pet fish, why not add their fishbowl to the arrangement! Accent with large shells.


Here are some great party supplies to help you create an undersea feel!

Ocean Preppy Boy Basic Party Pack
Ocean Themed Party Supplies
Under the Sea Basic Party Pack
Under the Sea Party Supplies
Mermaid Princess Deluxe Party Pack
Mermaid Princess Party Supplies
Tropical Fish Pinata
Tropical Fish Pinata
Ahoy Matey Basic Party Pack
Ahoy Matey Party Supplies
Shark Attack Deluxe Party Pack
Shark Attack Party Supplies


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Under the Sea Birthday Party Crafts

Paper Plate Jellyfish Materials: Paper Plates (cut in half and with a small hole punched in the top for hanging) Paint Glue Colored Streamers Construction Paper for Eyes Yarn or string to hang the finished craft Directions: Put out all the materials on a covered table. Have your guests paint the front of their plates. Make the face by cutting eyes out of construction paper and gluing them on. Then glue streamers to the back to make tentacles. When they are dry, thread a piece of yarn through the hole in the top and hang them up.

under the sea birthday party craft

Ocean framesBuy inexpensive frames at your local craft store. Paint them in under the sea theme colors. Put out small bowls containing shells, beads, gems, or other decorations, along with craft glue (or glue guns if a parent is supervising — these get very hot!)

beach theme frame crafts

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Under the Sea Birthday Party Activities

under the sea birthday party game

  • Dig for Buried Treasure — If you have access to a sandbox, scatter small ocean toys, shells, plastic coins and gems throughout. Give each child a sand pail and shovel and let them dig around for buried treasure. Little ones especially love this activity.


  • Crab Races — Have the children sit on the ground at the starting line. On the count of three, have them raise themselves belly up on their hands and feet and crabwalk backwards or sideways to the finish line.


  • Crab Soccer — Have the children get into their crab positions (belly up on their hands and feet) and play a game of crab soccer by using only their feet. (This works best with a lightweight ball.)


  • Flipper Relay — Divide the team into two groups for a relay race. Give each team a pair of swim flippers. Have the children take turns racing from point A to point B and back in their flippers. The first team with all its racers back wins. Make things even more challenging by having them carry a small bucket of water and seeing which team spills the least.


  • Sardines — This is a game of reverse hide and seek. Select one child to be “it”. Have that child find a good hiding spot while everyone else counts to 100. Then have everyone go look for the “it” child. As they find him, they should hide along with “it”. Slowly the party guests will disappear. The last child still looking will be “it” in the next game.

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Under the Sea Birthday Party Food


Here are a few “sea food” ideas for snacks and drinks at an under the sea birthday party:


  • Sea Animal Shaped Sandwiches Use ocean cookie cutters to create ocean sandwiches (peanut butter and jelly or tuna salad work well for this.) You could also use the newly available goldfish shaped bread from Pepperidge Farms — what could be easier!


  • Submarine Sandwich — Order a large sub sandwich from your local deli. Stick a flexible straw in the top for a periscope and use mayonnaise or other sandwich spread to adhere sliced olives to the sides for portholes.


  • Put out bowls of Goldfish Crackers


  • Egg Boats — Make deviled eggs, and then cut pieces of cheddar or American cheese into triangular shapes, thread them through toothpicks, and stick one in each egg to make a boat sail.


  • Fishie Cubes — The day before your party, place one fish shaped fruit candy into each compartment of an ice cube tray. Fill with water and freeze overnight to make floating fishie cubes for your drinks.


  • Deep Blue Sea Drink — Make a blue drink by mixing lemonade or apple juice with a little seltzer and adding a few drops of blue food coloring.


  • Shark Cupcakes — Bake your favorite flavor cupcake. While they are cooling, mix vanilla frosting with a few drops of blue food coloring in a small bowl to make ocean icing. Finally, cut a candy wafer in half or cut a wedge from a gummy candy to form a dorsal fin. Stick it into the middle of your cupcake.

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Party Favors

under the sea birthday party favors

Send your party guests home with a great memento of the day. Here are some suggestions:

  • Colorful sand pails and shovels
  • Sand toys shaped like sea creatures
  • Swedish Fish Candies or Gummy Fish
  • Frame and/or Jellyfish Party Crafts (See above)
  • Tubes of Sunscreen
  • Swim Goggles

Hope you found some useful under the sea birthday party ideas on this page. Hope your party is tons of undersea fun!

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If you enjoyed these under the sea birthday party ideas, you might also enjoy these parties:

luau birthday party
Luau Party
pool party ideas
Pool Party
pirate party ideas
Pirate Party


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