Remove the watermelon rind, and cut the watermelon into cubes.
Remove all of the seeds. You can remove the seeds with chopsticks, toothpicks, or the tip of your knife.
Place the watermelon cubes on a baking sheet lined with parchment paper. Make sure your watermelon cubes are not touching each other or they will stick together.
Place the tray in the freezer and freeze for 2-4 hours or until firm.
Store the cubed watermelon in a freezer-friendly container.