Cut the watermelon into manageable chunks, removing the rind and seeds if necessary.

Place the watermelon chunks into a blender or juicer and blend until smooth. Work in batches if needed.

Strain the watermelon juice through a fine-mesh sieve or cheesecloth into a large bowl or pitcher to remove pulp (optional, depending on your texture preference).

Juice the limes and add the lime juice to the strained watermelon juice.

Add honey or agave syrup if desired and stir well to combine.

Add 1 cup cold water to dilute slightly, adjusting to taste.

Refrigerate for 1-2 hours or serve immediately over ice for a refreshing drink.