Using a sharp knife and cutting board, chop the watermelon into 1-inch cubes. Measure out 3 cups and place in the blender jar.
3 cups cubed watermelon
Roll the lime on a hard surface to loosen the juice, then cut in half and squeeze into the blender. Add the fresh mint leaves on top of the watermelon.
1 lime lime, 8-10 leaves fresh mint leaves
Add the ice cubes to the blender, ensuring all ingredients are covered.
1 cup ice cubes
Secure the lid on the blender and blend on high speed for about 30-40 seconds, until the mixture is smooth and slightly frothy, with visible tiny bubbles and a vibrant pink color.
Stop the blender and check the texture. If the smoothie is too thick, add a splash of water or lime juice and blend briefly to incorporate. The finished smoothie should be cold, with a uniform, slightly frothy appearance.
Pour the smoothie into glasses, garnish with additional mint leaves if desired, and serve immediately with a straw or sip directly.
