Step 1
In a blender, puree the watermelon until smooth. Strain the puree through a fine mesh strainer to remove seeds and pulp.
Step 2
Pour the watermelon juice into an ice cube tray and freeze for about 3 hours.
Step 3
In a blender, combine 480 ml frozen watermelon cubes, tequila, lime juice, and sugar. Blend until smooth.