Place the cutting board on a stable surface and use a sharp knife to cut the watermelon into rough chunks, removing any seeds if necessary.
Measure 4 cups of watermelon chunks using a measuring cup and transfer them into the blender.
Add a pinch of salt to the blender to enhance the natural sweetness and aroma.
Secure the lid on the blender and blend on high speed until the mixture is completely smooth and frothy, about 30 seconds. You should see a vibrant red liquid with a silky consistency.
Pour the blended watermelon into glasses, ensuring an even distribution of the liquid. Serve immediately for the best chilled, refreshing texture.