First cut the watermelon into smaller pieces.
Add the cut watermelon to a blender or food processor along with the water and sugar. Blend until smooth and there is no longer any chunks.
If you want the drink to be thinner, you can strain it into a juice but I prefer it more thick.
Add 4 to 6 mint leaves at the bottom of a cup along with 1-2 to lime slices. Use a muddler or wooden spoon to crush the mint and lime to release the flavors. Alternatively, you can add the mint and lime juice to the blender along with the watermelon instead of this step.
Add ice cubes and pour the watermelon juice into the cup. Give it a mix and enjoy!