Collage of under the sea party decorations

DIY Under the Sea Party

I love throwing birthday parties for my kids. I know that they are too young to remember them, but that doesn’t stop me from wanting to make them fun and exciting. After getting a water themed water bottle and having a brief pufferfish obsession, my just turned three daughter decided she wanted an under the sea party.

My daughter is old enough that I let her invite some of her friends for the first time. This gave me the extra challenge of throwing an under the sea party that not only my three year old would enjoy, but also her friends ranging from one to nine years old.

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How to Throw an Under the Sea Party

Invitations For an Under the Sea Birthday Party:

Instead of ordering personalized invitations, I used a free design online. Then, I printed it out on cardstock, cut it with my paper cutter, and mailed it in normal envelopes. I modified this cute under the sea baby shower invitation from Greetings Island into an under the sea birthday party invitation.

Food for an Under the Sea Party:

Beach Cake:

My daughter loves the concept of cake for birthdays. But give her cake and ice cream and the ice cream will be gone in less than a second and the cake will be forgotten about. So, I knew I needed to make her an ice cream cake. I decorated her three shaped under the sea birthday party cake with a beach theme including lots of seashells. Get familiar with this seashell mold as I used it A LOT for this party. You can get more detailed instructions here on how to make this beach cake, including using your own shape or cake recipe.

Picture of a beach themed ice cream cake with seashells on top for an under the sea birthday party

Squid Veggie Tray

I got this really cute idea from this picture and modified it to work with my veggie tray. To start, I cut a red pepper into the squid shape and glued on googly eyes. I cut a chunk off the back of the pepper to have enough for the legs. Then, I placed cucumber, carrot, and broccoli around it to make it a full veggie tray.

Picture of a squid shaped red bell pepper

Clam Cantaloupe

I really liked this watermelon clam idea, but watermelons were out of season. However, I could find a cantaloupe, so I used it instead. First, I cut a wedge from the middle. Then I carved out as much cantaloupe from the middle as I could. Next, I cut wavy lines across the mouth. Finally, I glued on googly eyes and filled it back up with the cantaloupe I dug out.

Beach Pail Snack Mix

For my snack mix, I filled a beach pail with popcorn, rainbow goldfish, and pretzel goldfish. This was the first time my daughter had the pretzel ones and has been asking for them ever since. (I am updating this post over a year later and they are still her favorite.) I have a silicone popcorn popper that I absolutely love that I used to make the popcorn in the microwave. Finally, I stuck a beach pail shovel in as the serving spoon. I thought it was a fun addition for an under the sea party.

Picture of beach pail filled with popcorn snack mix

Seashell Ocean Punch

Punch is one of the easiest drinks to theme for a party. To get an ocean blue color I followed this cool blue pool punch recipe. Then, I used my seashell mold (told you it was going to keep showing up) to make seashell ice to go in it.

Picture of blue punch with seashell ice cubes

Decorations For an Under the Sea Birthday Party:

Overhead Fish Silhouettes

These fish silhouettes were probably the easiest decoration to make. We live in a bilevel, so this was hanging overhead right when people came into our house. I loved the strong first impression of the theme. You can find the directions and patterns here.

Picture of blue tablecloth with fish silhouettes hanging over

Bubble Wrap Octopuses

If you are familiar with this blog, these might look really familiar. I made smaller bubble wrap octopuses with magnets for the fridge a few months ago. For this party, I reused this idea, but made them even bigger. Instead of crumpling up paper, I used balloons to fill the heads. Then, I hung them on the back door along with blue streamers.

Outdoor Decor

I was so concerned about the weather for my daughter’s birthday. With where we live, days in March can be a nice and sunny or a blizzard. Our house would be really crowded with all her friends and family, and I wanted space for the kids to run around. I finally decided that we would have most of it outside if it was a nice day and clean out the garage and put a space heater in it if it wasn’t. Thankfully, it was a nice day and were able to go outside.

I did minimal decorations outside, since they all needed put up the day of the party. The biggest decoration was a net made from a string trellis filled with balloons. To keep the balloons from blowing out of the holes, we had to tape all but the biggest balloons to the staircase. On the outside of the net we taped little sea creatures that I had cut out using this fish pattern. We also taped blue streamers to the deck along with an attempted jellyfish garland that looked nothing like jellyfish. Lastly, we taped green streamers onto the fence to look like kelp along with more of the sea creatures.

Activities for an Under the Sea Birthday Party:

Pufferfish Pinata

As previously mentioned, my daughter went through a brief pufferfish obsession. Once she said she wanted an under the sea birthday party, I knew something had to be a pufferfish. I decided that something was going to be a pinata. Pinatas are such a classic little kids birthday party game and I was really excited to introduce one to my daughter. I made her pufferfish out of paper mache and you can get the detailed instructions here.

Picture of a pufferfish shaped pinata hanging outside

Sticker Making

I also wanted a few activities kids could do on their own. I figured these would be good for keeping kids entertained while waiting for everyone to show up. One of these activities was coloring and decorating their own stickers. You can find the pattern and instructions here.

Picture of box with markers, crayons, and under the sea party stickers

Seashell Hunt

For another individual activity, I thought a simple seashell sand hunt would be lots of fun. This was a hit for several of the kids, including my one year old son. Here are more details about our seashell sandbox treasure hunt.

Picture of sandbox with seashells ready for a sandbox treasure hunt with a bucket of supplies next to it

Goodie Bags:

With my daughter having friends come this year, I wanted to send home favors. I got each kid a beach pail and labeled it with their name next to a cute sea creature. Next, I put in chalk and crayons that my daughter helped me make using the seashell mold (last time, I promise). We had made crayons before, but this was our first time making chalk.

Then, the kids got to add to their pails as they did things at our under the sea birthday party. They got candy from the pinata, seashells and a shovel from the seashell hunt, and stickers from the sticker making. I made labeled bags for each of the items they received. Here are my under the sea party labels: chalk, crayons, candy, seashells, and stickers.

Conclusion of My Daughter’s Under the Sea Party

I think that everyone had a lot of fun at my daughter’s under the sea 3rd birthday party. My daughter had a blast and has been wanting another birthday ever since. Let me know in the comments if you use any of these fun ideas for your own party. If you are looking for more themed games and a magical pearl story check out these under the sea ideas from Parties Universe.

Also, check out my son’s knight and dragon themed birthday for more fun party ideas.

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