Little Splash, Big Party
“Planning the Perfect Under the Sea Bash”
Let me take you on a journey — one filled with streamers, frosting, and tiny mermaids doing the worm on my living room floor. When my daughter announced she wanted a “real mermaid party” for her birthday — and not just any mermaid party, but an “under the sea enchanted coral reef with jellyfish and treasure and dolphins and shells that sparkle” — I knew I was in trouble.
Credit: Lily’s Under the Sea themed Party by PartyDish Event Styling
So what did I do? I flipped my fins and got to work. I’m talking DIY décor, budget-friendly snacks that looked like they swam in from Pinterest, and a cake that leaned a little but still slayed. And the best part? I found the cutest free invitations that didn’t cost me a single pearl. So if you’re looking to throw a splash-tastic bash your little guppy will never forget, you’re in the right tidepool.
Our House Became the Ocean and …
“My Couch Became a Coral Reef”
When you don’t live inside a Disney castle or next to a magical lagoon, you do what every party-loving mom does: fake it with glitter and a lot of tissue paper. We turned our backyard into a full-blown mermaid lagoon using nothing but blue streamers, two inflatable seahorses, and a bubble machine that kept blowing soap directly into Grandma’s coffee. It was a whole vibe.
Credit: Under the Sea Backyard Birthday Party by Momo Party
The swing set became “Mermaid Rock,” where the birthday girl sat in a glittery tail (that I may or may not have bribed her to wear with candy). We even added a “treasure sandbox” — basically a plastic bin filled with kinetic sand and plastic jewels. The kids went nuts. One boy dug up a fake gold coin and yelled, “I’M RICH!” and refused to take it out of his sock for the rest of the day.
Credit: Under the Sea Birthday Party Ideas by Greenvelope
If you’re stuck indoors, don’t worry. Our backup plan included turning the living room into a mermaid cove with streamers on the ceiling (aka seaweed), paper lantern jellyfish, and enough teal fabric to rival Ariel’s dress closet. Fairy lights added that sparkle-sunlight-through-water vibe, and honestly, it looked so good my toddler asked if we were underwater for real.
Calling All Mermaids and Mates
“Free Under the Sea Invitations”
Let’s talk invites. I used to think you had to drop $40 on Etsy to have something that didn’t scream “I made this in Word.” But then I discovered these adorable free Under the Sea birthday invitation templates. Y’all. They’re chef’s kiss. I picked one that had a watercolor mermaid surrounded by coral and sparkles and edited the text to say “Join Us Under the Sea!” It took me like 10 minutes on Canva and I felt like a graphic designer with a side hustle.
There were other designs too — one looked like a treasure map, another had cartoon fish and bubbles, and one had the cutest little seahorse with a pastel shell crown. I honestly wanted to throw four different parties just so I could use them all. I printed a few on cardstock and handed them out old-school. The rest I sent via text, which saved trees, postage, and my sanity. One mom said, “This is the cutest invite I’ve ever gotten.” I said thank you and pretended I wasn’t wearing my robe while finishing it.
Once personalized, print them on cardstock for a high-quality look or send them digitally for a quick and eco-friendly option. For an extra-special touch, roll printed invitations into mini scrolls and tie them with twine, or add a sprinkle of glitter to the envelopes for a surprise your guests will adore.
CUSTOMIZE AND DOWNLOAD NOW ON CANVA!
Beginner’s Guides
Before you get too wrapped up in planning the rest of your party magic, let’s talk about invitations! Our free invitation templates are not only adorable, but they’re super easy to customize too. Whether you’re adding in party details like the date, time, and location or even a special note, you can personalize everything to fit your theme perfectly.
A. Download Instruction
Want to know how? Read this step-by-step guide to help you download and customize our free editable invitation templates:
- Scroll up the page until you see the “Download Free Editable … Here” button.
- A new page will be shown in seconds, and you will be able to see the preview of our template designs.
- Choose/click the “Edit Template” button (blue button).
- Now you can personalize our templates, like putting your son or daughter’s name, changing the font-size and color.
- Once you finished with the editing, you can download the final draft (Go to File > Download > Select the File Type (PNG is the best option) > Download.
B. How to Print the file?
“Steps for printing our templates”
- Save the image you want to print to the computer or to a flash drive if it is not saved already. (Step 5 of Download Instruction).
- Go to the file explorer and find the file. Double click the image.
- The file will open in Windows Photo Viewer
- Go to print at the top and then go to the print option
- Select the color printer if you want the photo to print in color
- Select the print size you want
- You may want to play around with the “Fit picture to frame” option. Sometimes that option will allow the photo to print closer to the border, but sometimes it will cut off the edges of the photo.
- Hit print and Voila!!!
Speaking of birthday parties, we avoid to see anything basic, especially when it comes to children’s birthdays. By unusual, I mean something that isn’t typical Floral theme, but rather something like what’s in this page or something like these, Cutest Under the Sea and Whimsical Watercolor Under the Sea birthday invitation templates.
Sea-worthy Snacks and a Show-stopping Cake
Okay, the cake. Let’s be honest — I tried to make a mermaid tail cake. I baked two layers, stacked them, carved the tail shape, and… well. The tail kinda sagged. It looked more like a sea cucumber wearing a tiara. But I covered it in aqua frosting, slapped on some edible pearls and shell candies, and it was good to go.
Credit: Blue and Gold Under the Sea Cake by Simply Sweet Cupcakes
Bringing in cupcakes was my redemption. I frosted them with blue and lavender swirls, sprinkled edible glitter like I was casting a sea spell, and topped each with a tiny starfish pick. I even arranged them on a cake stand shaped like a treasure chest. The whole thing was giving: nautical elegance meets sugar overload. Brb, trademarking that aesthetic.
Under The Sea Art Time
“Coloring Pages and Crafts That Spark Joy”
After all the sugar, the kids needed to chill before someone body-slammed a balloon octopus. That’s where the coloring station came in. I printed out Under the Sea coloring pages with dolphins, mermaids, and treasure chests, and set up a table with crayons, markers, glitter pens, and those sticker sheets that somehow end up on your couch six weeks later. The kids LOVED it.
Credit: Mermaid Coloring Pages Templates by Kids-n-fun
One girl drew a crab in a tutu and named her “Princess Clawdia.” Another made a rainbow narwhal with a sword. A tiny boy covered every page in gold glitter glue and shouted, “IT’S THE SUN UNDERWATER!” Honestly? Art. We also had a jellyfish-making table where kids made their own jellies using paper bowls, ribbon, and googly eyes. One jellyfish had fangs. One had earrings. It was chaotic, adorable, and oddly inspiring.
The Magical Moment That Made It All Worth It
By the time the last bubble popped and the last streamer fell off the wall, I was sticky, exhausted, and holding a mermaid tail that had been stuffed with Goldfish crackers. But my daughter ran up to me, arms full of glittery crafts, and whispered, “This was the best day of my whole life.”
So if you’re reading this wondering if you can pull off an Under the Sea party without losing your mind, trust me. You absolutely can. You don’t need a castle. You don’t need a yacht. You just need some dollar store glitter, a solid playlist, and enough snacks to feed a sea monster. Now go get your sparkle on, mama. It’s time to party like a mermaid.
FAQs:
1. What’s the best way to decorate for an Under the Sea party?
Use blue and green streamers, cutouts of sea creatures, and paper lanterns as bubbles. DIY decorations like a treasure chest or a mermaid grotto can add extra flair.
2. How do I make a sea-themed cake without professional skills?
Buy a plain frosted cake and decorate it with store-bought toppers like sugar seashells, edible pearls, or a plastic mermaid figurine. Cupcakes are another easy option—just add blue frosting and sprinkles.
