Add the watermelon to your blender, then purée until smooth.
Place a fine mesh strainer over a bowl, then strain the puréed watermelon to remove the pulp.
Discard pulp, then measure one cup of strained watermelon juice (save extra juice for another use). Add the juice to a mason jar (or other container), along with the sugar.
Stir the watermelon-sugar mixture for a couple minutes. Then let the mixture sit until the sugar is totally dissolved, stirring every 5 to 10 minutes. It should take about 30 to 45 minutes total.
Prepare Soda:
Add ¼ cup watermelon syrup to a glass, then stir in the sparkling water.
Fill glass with ice, then serve. Enjoy!
Notes
Syrup - This recipe makes enough syrup to prepare 6 sodas. The syrup can be made in advance and stored in the refrigerator for up to 2 weeks. Check out my Watermelon Syrup recipe for more ways to use this delicious syrup!Sweetness - It's easy to customize this drink to taste! Just add more (or less) syrup to make it sweeter (or less sweet).More - Check out the info before this recipe card for helpful tips, variations, and more watermelon drink ideas!