Combine the water, sugar, and salt in a saucepan to create a simple syrup.

Peel the watermelon and cut the flesh into cubes.

Puree in a blender and strain through fine mesh.

Juice the limes and add to the watermelon juice.

Pour in the watermelon juice and club soda and stir gently.

Chill well and serve over ice

Sparkling  Watermelon Mocktail