Step 1

In a saucepan, combine the sugar and water.

Step 2

Heat the mixture over medium-high heat, stirring occasionally until the sugar is completely dissolved.

Step 3

Once the sugar has dissolved, remove the saucepan from the heat and let it cool to room temperature.

Step 4

Once the mixture has cooled, transfer it to a clean bottle or jar, and store it in the refrigerator until you're ready to use it.

Step 5

Blend the cubed watermelon, sliced cucumber, and fresh mint leaves in a blender until smooth.

Step 6

Pour the mixture into a large pitcher, then add the vodka, lime juice, and simple syrup. Stir well to combine.

Step 7

Fill the pitcher with ice cubes and top it off with the club soda.

Step 8

Give the mixture a gentle stir and serve immediately.