To make watermelon juice you want to take a sharp knife and cut the watermelon to separate the melon from the watermelon rind. It’s a good idea to cut it into smaller pieces or watermelon cubes if possible. If you prefer you can use a melon baller to scoop out the inside of the watermelon.
Place the cut watermelon into a blender. Add in lime juice, and your desired sweetener if desired. Cover with the lid to the blender, and then blend until the pieces are smooth.
Pour the watermelon juice through a fine mesh strainer, to remove any watermelon flesh.
Serve your fresh watermelon juice over ice cubes, with fresh mint leaves, and enjoy!