There are several ways you can water proof your paper boat: 1. Start with waterproof paper. 2. Drip hot candle wax on the areas of the finished folded paper boat that you want water-proofed. 3. Spray your finished paper boat with a waterproofer water repellent like a boot spray. 4. Before you fold your boat, slip your paper into a clear sheet protector cut to size and follow the folding instructions. You may need a little tape to reinforce a fold since the paper is now bulkier. 5. Before you fold your paper boat, laminate the paper you are using and then follow the folding instructions. 6. This isn't a long term waterproofing solution, but coloring what will be the bottom portion of the boat before folding with wax crayons with a thick, colorful layer can hold off the water for a bit!