Over medium heat, bring honey, water, and fresh mint to a boil, whisking occasionally. Once the syrup has reached a boil, remove from heat and allow to cool to room temperature, about 30 minutes or so.

With a blender or food processor, puree watermelon and lemon juice together. Strain the mixture through a sieve to remove the pulp (if you do not mind pulp, you can skip this step).

Pour the watermelon juice and lemon juice into a large pitcher.

Remove mint from simple syrup, and pour the syrup into the pitcher.

Add in 3 cups of water (this is to taste, so you can add more/less water until it reaches your desired flavor).

Stir the mixture.

Refrigerate until ready to serve.

Serve with ice, lemon wedges, or fresh mint, if desired.