Use a chef's knife and cutting board to dice the watermelon into small, uniform cubes.
Peel, pit, and chop the avocados into chunks approximately the same size as the watermelon pieces, displaying a creamy, green interior.
Transfer the diced watermelon and chopped avocados into a large mixing bowl, gently combine using a spoon or spatula without mashing the fruit.
Gently fold the ingredients together until evenly mixed, observing the contrast of bright red and green colors.
Serve immediately in bowls, showcasing the vibrant mixture with a slightly glistening appearance from the natural juices.