Using a sharp knife, cut your watermelon into 1 inch chunks.
Combine watermelon and vodka in a mason jar.
Let sit for 2 days, or up to 5 days.
Set a fine mesh strainer over a medium bowl. (Optional: Line the strainer with cheesecloth.)
Strain the mixture through the strainer.
Enjoy your vodka.
Store at room temperature for up to 6 weeks or in the refrigerator for up to 3 months.