Homemade Bath Crayons for Kids

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Want to make a fun and easy stocking stuffer or gift for your kids? These homemade bath crayons will make bathtime more creative, colorful, and exciting.

After testing a few different recipes, I’m sharing an improved version that draws better on bathtub walls and is still safe and gentle for kids.

Supplies You’ll Need:

• Clear glycerin soap base (or white if you want pastel crayons)

• Liquid soap coloring or food coloring

• Essential oils (optional) – We used lemon and orange

• Silicone molds (ice cube trays, crayon molds, or mini muffin molds)

• Cornstarch (this is the key to better writing texture!)

Optional: Try cosmetic mica powder for deeper pigment

Why Add Cornstarch?

Adding a bit of cornstarch gives the crayons a firmer, more matte texture—making them more similar to real crayons and helping them actually show up on wet surfaces.

How to Make Homemade Bath Crayons:

1. Cut the glycerin soap base into small chunks and place in a microwave-safe bowl.

2. Melt the soap base in 30-second intervals, stirring in between, until fully melted.

3. Mix in a teaspoon of cornstarch for every 1/4 cup of soap base. Stir thoroughly.

4. Add a few drops of soap coloring and essential oil, if using. The more color you add, the better the crayons will draw.

5. Quickly pour the mixture into your silicone molds before it begins to harden.

6. Optional: Chill in the fridge for 20 minutes to set faster.

7. Once hardened, pop them out of the molds and let them sit for 24 hours to fully dry.

Using Your Bath Crayons

These soap crayons are great for drawing on bathtub walls, tiles, or shower doors. They wash off with warm water and a little scrubbing.

Tip: The smoother the surface, the better they work. Textured tubs may reduce visibility.

See also our homemade bath bombs!

Fun Variations to Try

• Swirled colors (pour two colors in at once and swirl with a skewer)

• Layered rainbow crayons

• Add natural scents like lavender or mint

• Use alphabet or shape molds for a learning tie-in

Science & STEAM Tie-In

Use this as a lesson on solids and liquids, mixtures vs. solutions, and how soap can be both a solid (bar) and a liquid (when melted). Let kids measure, melt, pour, and observe how things change.

Bath crayons are such a fun way to turn an ordinary bath into a creative, colorful experience. With this easy DIY recipe, you’ll have a batch of vibrant, kid-safe soap crayons that actually work—and that your kids will be excited to use again and again. Whether you gift them, make them for a rainy day, or add them to a themed STEAM activity, these homemade bath crayons are sure to be a hit!