Put watermelon cubes in a blender together with water, lemon juice and sugar. Blend until smooth. Taste and adjust to your taste by adding more lemon juice or sugar.
Strain the liquid to remove pulp.
Pour into a glass and add some ice cubes. Garnish with thin slices of watermelon. Serve immediately.
Recipe Notes
*Add more or less water, depending how strong watermelon taste you want.