Start by cutting away the rind from a ripe watermelon, ensuring to remove all green areas. Chop the watermelon flesh into approximately 1-inch cubes.

Take a Ninja Creami pint container and fill it with watermelon cubes, stopping at the max fill line. Pack loosely to allow for expansion.

Pour coconut water over the watermelon cubes in the container, filling to the max fill line.

Secure the lid tightly and place in a freezer set at 0°F (-18°C) for 12 to 24 hours.

Once frozen, remove from freezer. Microwave for 30 seconds or submerge under hot water briefly to soften.

Place the softened mixture into your Ninja Creami and select the sorbet setting. Re-spin if necessary for smoothness.