Place the watermelon cubes in a blender or food processor and blend until completely smooth.

Strain the watermelon puree through a fine-mesh sieve into a large bowl to remove any pulp for a smoother texture.

In a small saucepan, combine the sugar and water over medium heat. Stir until the sugar is fully dissolved, then remove from heat and let cool completely.

Mix the cooled sugar syrup, lime juice, and lime zest into the watermelon puree. Stir well to combine.

Pour the mixture into a shallow, freezer-safe container. Cover and freeze for 1 hour.

After 1 hour, stir the mixture with a fork to break up ice crystals. Repeat this process every 30 minutes for 3-4 hours, or until the sorbet is fully frozen and has a smooth texture.

Once fully frozen, scoop the sorbet into serving bowls or cones and enjoy!