Begin by cutting one seedless watermelon into manageable pieces, removing any seeds, aiming for approximately 4 cups of cubed watermelon.

In a high-speed blender, add the watermelon cubes and blend on high until you achieve a smooth puree, about 30 seconds.

For an ultra-smooth Watermelon Limeade, strain the puree through a fine mesh sieve over a bowl, discarding any pulp.

In the blender, add fresh lime juice and sweetener, then blend for about 15 seconds until well combined.

Pour the blended mixture into a large pitcher, stirring in 2 to 4 cups of cold water or sparkling water.

Fill glasses with ice cubes and pour the Watermelon Limeade over the top, garnish with mint or a lime wedge.