Use a knife and cutting board to cube the fresh watermelon flesh into small, manageable pieces.
2 cups fresh watermelon flesh
Place the watermelon cubes into the blender jar.
2 cups fresh watermelon flesh
Add the cold water to the blender, pouring slowly until the liquid covers the fruit by about half.
0.5 cups cold water
Secure the lid on the blender and blend on high speed until the mixture is evenly combined and slightly frothy, about 30 seconds. Look for a uniform, semi-translucent texture.
Pour the blended watermelon juice through a fine mesh strainer or cheesecloth into a pitcher to remove pulp and seed particles, resulting in a smooth, cloudy liquid.
Serve immediately in glasses, observing the semi-transparent, slightly frothy appearance with visible specks of watermelon pulp.