These under-the-sea crafts and activities are a playful way for children to explore nature and ocean life. They’re perfect for an Under the Sea birthday party, a camp day, or simply a creative afternoon. Many projects are aimed at toddlers but can easily be adapted for older kids.
Shell Crafts
Use real shells from the beach or make your own from household materials. These ideas celebrate the unique shapes and textures of shells in easy, kid-friendly projects.
Seashell Creatures
Create tiny characters using store-bought or beach-found shells combined with air-dry clay for bodies. These sweet creatures are great for pretend play in a sandbox or as shelf decorations.
Photo source and inspiration by The Decorated Cookie
Wall Hanging Seashell Craft
Make a decorative wall hanging by securing shells to cotton cord and attaching the cord to a wooden dowel or piece of driftwood. This simple project works well in a nursery, a child’s room, or as unique home décor.
Photo source and inspiration by Lovely Indeed
DIY Sea Creature Crayons
Repurpose broken crayons by melting them into sea creature molds to create colorful, reusable crayons. It’s a simple recycling craft that yields fun, usable results for art time.
Photo source and inspiration by Pint Sized Treasures
Cupcake Paper Seashell Art
Cupcake liners have natural pleats that resemble shells. Kids can cut, paint, and glue liners onto cardboard to compose textured sea-inspired artwork.
Photo source and inspiration by Handmade Charlotte
DIY Painted Seashells
Turn a shell collection into colorful décor by painting shells in bold hues. Painted shells can brighten a room or serve as a hands-on activity at an ocean-themed party.
Photo source and inspiration by Handmade Charlotte
Clay Seashell Craft
Press shells into air-dry clay to create textured impressions. Paint or embellish the clay with beads or faux pearls for extra detail. This project is simple and produces keepsake pieces.
Photo source and inspiration by Hello Wonderful
Under The Sea Party Favor Photo Backdrop Craft
Cut craft paper into seaweed and shell shapes, and use brown paper for the ocean floor. Add small photos inside shell shapes to create a personalized favor or keepsake backdrop for party guests.
Photo source and inspiration by Mama.jots (Instagram)
Water Theme Activities & Crafts
Sensory play supports development in toddlers. These water-based and sensory activities bring the sights and sounds of the ocean to life while encouraging hands-on exploration.
Ocean Sensory Bag
Fill a resealable bag with ocean-themed items—small toys, glitter, and blue gel or water—to make an entertaining, tactile sensory bag that captures toddlers’ attention.
Photo source and inspiration from Kids Activities Blog
Just Add Water
Quick water play ideas create an ocean-like experience with minimal setup. Use toys you already own and a container of water for instant fun.
- Run sprinklers and let kids pretend they’re beneath a waterfall.
- Scatter rocks in a kiddie pool for a simple “sea floor” treasure hunt.
- Float toy boats in a sink, tub, or pool for imaginative play.
- Water plants and imagine they’re seaweed or anemones swaying underwater.
Bubble Painting
Bubble painting combines art and sensory play. Mix two parts non-toxic paint with three parts bubble solution, then have kids blow bubbles onto watercolor paper to create lively, bubbly patterns. Because acrylic paint can stain, this is best done outdoors.
Adjust paint or bubble solution for brighter colors or more foam, and allow finished pieces to dry in the sun.
Fish Crafts
Fish and other sea creatures are endlessly fascinating for kids. These simple crafts highlight familiar ocean animals with materials you likely have at home.
Handprint Crab
Trace little hands on colored paper to form crab shapes, then add googly eyes and drawn details. Handprint crafts are easy keepsakes and a favorite among toddlers.
Find the full tutorial by Simple Everyday Mom
Circle Punch Paper Fish
Let kids use circle punchers to create colorful scales. Cut a fish shape from paper, glue punched circles as scales, then finish with a googly eye and marker details for a textured, bright fish.
Under the Sea Paint Swatch Collage
Collect paint swatches and cut them into shapes like fish, seahorses, and seaweed. Arrange and glue the shapes onto poster board or watercolor paper to make a colorful ocean collage.
Photo by Studio DIY
Jellyfish Paper Plate Craft
Paint paper plates blue, add googly eyes, and attach string or paper strips through punched holes to create jellyfish tentacles. This lightweight craft is easy for small hands.
Photo source and inspiration by ConservaMom
Paper Mache Fish
Paper mache offers a fun, messy way to build three-dimensional fish using recycled paper and paste. Make a school of fish to display on a child’s shelf or use them as party decorations.
Photo source and tutorial via Studio DIY
Origami Fish Craft
Origami fish are a paper-only craft that’s surprisingly simple. With a few folds and added eyes, kids can make plenty of smiling fish in just minutes.
Photo source and inspiration by Mommy Made That
DIY Moon Sand
Homemade moon sand mimics beach sand and works wonderfully for sensory play. Provide molds shaped like crabs, starfish, or castles to extend imaginative play.
Photo source and inspiration by Childhood Magic
Under The Sea Diorama
Build a three-dimensional underwater scene inside a box. Younger children can paint a background, add blue tissue for water, and glue paper sea creatures to create a mini ocean habitat.
Photo source and inspiration by Almost Makes Perfect (Instagram)
Killer Whale Paper Bag Puppet Craft
Create orca puppets from paper bags, construction paper, and glue. These make great props for an ocean-themed puppet show and are suitable for preschool and elementary-aged children.
Photo source and inspiration by Simple Everyday Mom
Light up Tropical Reef Craft
Repurpose an egg carton to build a glowing reef filled with tissue paper, LED tea lights, and pipe cleaner stems. Add paper fish on top so it appears alive and shimmering in the dark.
Photo source and inspiration by The Craft Train
Mermaid Crafts
Salt Dough Starfish
Make salt dough, roll it out, and cut starfish shapes. After baking or air-drying, kids can paint and decorate with glitter, beads, or faux pearls. This is a fun group activity for parties.
Photo source and inspiration by The Mama Notes
DIY Glitter Ocean Slime Jars
Create “aquariums” in jars by filling small containers with glittery slime and tiny toy sea creatures. These jars are calming, tactile, and visually appealing for kids.
Photo source and inspiration by A Pumpkin & A Princess
More Activities and Crafts for Kids
- 24 Bug Crafts & Activities for Kids
- Wild Animal Crafts and Activities
- Rainbow Crafts and Activities
- Space Crafts and Activities
- Ice Cream Crafts and Activities
- Music Crafts and Activities
- Shapes Crafts and Activities
The ocean offers endless inspiration. Whether you’re planning an ocean- or mermaid-themed party or simply looking for creative ways to engage your ocean-loving children, these crafts and activities provide hours of imaginative, hands-on fun.