Add the chopped peaches, lemon juice, honey, and 1 cup of the water to a blender. Blend on high speed for 45-60 seconds until completely smooth and no peach chunks remain.
Gently tear or bruise the mint leaves with your hands to release their oils, then add them to the blender. Pulse 3-4 times just to incorporate — over-blending mint creates bitterness.
Pour the peach-mint mixture through a fine-mesh strainer into a large pitcher if you want smooth lemonade, or pour directly into the pitcher for a more textured drink.
Add the remaining 3 cups of cold water to the pitcher and stir well to combine. Taste and adjust sweetness if needed by stirring in additional honey.
Refrigerate for at least 30 minutes to let flavors meld and the lemonade chill thoroughly.
Serve over ice in tall glasses, garnished with fresh mint sprigs and peach slices. Stir before pouring since natural separation may occur.
