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

Strain the watermelon puree through a fine-mesh sieve into a large bowl to remove pulp and seeds. Discard the solids.

In a small saucepan, combine the sugar and water. Heat over medium heat, stirring occasionally, until the sugar dissolves completely to create a simple syrup. Allow it to cool to room temperature.

Mix the cooled simple syrup and lime juice into the watermelon puree, stirring until fully combined.

Pour the mixture into an ice cream maker and churn according to the manufacturer's instructions, typically about 20-25 minutes.

Transfer the churned sorbet into an airtight container and freeze for at least 2 hours to firm up before serving.

Scoop and serve the watermelon sorbet in bowls or cones. Enjoy!