01 - Combine watermelon, mango, and lime juice in a blender. Blend until completely smooth, about 30-45 seconds.
02 - Divide the fruit puree evenly among 4 tall glasses, filling each about one-third full.
03 - Pour ½ cup chilled lemon-lime soda into each glass. Stir gently with a spoon to combine the flavors while maintaining some fizz.
04 - Place a generous scoop of vanilla ice cream on top of each drink. The ice cream will slowly melt into the fruity mixture.
05 - Add fresh mint leaves to each glass if desired. Serve immediately with a straw and spoon for the best texture and temperature.