In a large saucepan, bring 3 cups water to a boil. Remove from heat, add the tea bags, and let steep for 10 minutes. Discard the bags and allow the tea to cool to room temperature.
Stir in the honey, plums, and thyme. Transfer to a pitcher and refrigerate until cool, about 1 1/2 hours. Serve over ice.
For an instant cocktail: Stir in 1/2 cup bourbon before serving.