Dice the watermelon into roughly 1-inch cubes and measure out 4 cups. Place the cubes into the blender.
4 cups watermelon cubes
Add the freshly squeezed lemon juice and honey (or agave syrup) to the blender with the watermelon.
4 cups watermelon cubes
Drop in the basil leaves into the blender, spreading them evenly over the fruit mixture.
4 cups watermelon cubes
Blend the mixture on high speed for 30-45 seconds until the juice is vibrant pink and smooth, with some pulp remaining for texture.
Place a fine mesh strainer over a pitcher and pour the blended liquid through it, using a spoon to press out excess pulp and basil oil. Discard solids.
4 cups watermelon cubes
Serve the lemonade over ice, garnished with a sprig of basil and a lemon wedge if desired. Enjoy immediately for the freshest flavor.
4 cups watermelon cubes