Add sugar and water to a medium saucepan. Place the pan over medium heat and stir until the sugar dissolves completely.
Fill a 2.5-quart pitcher with ice. Pour the warm simple syrup over the ice to cool it down.
Add the pineapple juice, lemon juice, and sparkling water to the pitcher. Stir everything together.
Chill until ready to serve.
Notes
I like to add fresh mint to the pitcher and serving glasses for a little extra freshness on hot days.If you want to make this spiked lemonade, add 1 1/2 cups of white rum or coconut rum and some fresh pineapple chunks.