Chop the watermelon into small chunks and remove any seeds. Place the watermelon and coconut water into a blender or food processor and process until well blended.

Place silicone molds onto a baking sheet for stability. Pour the liquid into the molds until full. Place the molds in the freezer for 2 hours or until frozen solid.

Remove the treats from the molds and place them in a plastic freezer bag or freezer-safe container. Store them in the freezer for up to 3 months.