In a large mixing bowl, combine the watermelon gelatin with 1 cup of boiling water. Stir gently with a whisk for about 2-3 minutes, ensuring the gelatin dissolves completely without any lumps.

Allow the gelatin mixture to cool at room temperature for about 15-20 minutes.

Once the gelatin mixture has cooled, gently fold in 2 cups of thawed Cool Whip using a spatula.

Carefully add in 2 cups of diced, seedless watermelon to the whipped mixture and fold gently.

Pour the fluffy filling into the prepared graham cracker crust, smoothing the top.

Cover the pie with plastic wrap and place it in the refrigerator to chill for at least 2 hours.

After chilling, remove the Watermelon Pie from the refrigerator and slice it into wedges.