Cut up the watermelon into chunks and remove any black seeds.
Put the watermelon and coconut milk into a high-powered blender and blend until you have a puree.
Pour the watermelon popsicle mixture into six popsicle molds. Leave a ¾ inch gap between the liquid and the lid to allow for expansion. Add the lid to each popsicle mold and then freeze it for 2-3 hours or until fully frozen.
Notes
Freeze for at least 2 hours to ensure they are frozen throughout. Depending on the popsicle mold you use, you may need to freeze them for longer.