01 - Combine the watermelon, mango, and lime juice in a blender. Blend until completely smooth, ensuring no fruit chunks remain.
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 to combine the fruit puree with the soda while maintaining some carbonation.
04 - Place a generous scoop of vanilla ice cream on top of each drink. The ice cream will create a creamy float effect as it melts into the fruit mixture.
05 - Garnish with fresh mint leaves if desired. Serve immediately with a straw and spoon to enjoy both the liquid and frozen elements together.