Place the watermelon cubes into a blender or food processor. Blend until smooth.

Strain the watermelon puree through a fine mesh sieve into a large bowl to remove any pulp, if desired.

In a small saucepan, combine the sugar, lemon juice, and water over medium heat. Stir until the sugar has completely dissolved, then remove from heat and let the mixture cool completely.

Mix the cooled sugar syrup into the watermelon puree until well combined.

Chill the mixture in the refrigerator for at least 1 hour to ensure it is cold before churning.

Pour the chilled mixture into your ice cream maker and churn according to the manufacturer's instructions, typically 20-30 minutes.

Once the sorbet reaches a thick, creamy consistency, transfer it to an airtight container and freeze for an additional 2-4 hours to firm up.

Serve the watermelon sorbet in bowls or cones and enjoy!