Preheat your oven to 350°F (175°C). Grease a loaf pan.
In a mixing bowl, combine flour, sugar, baking powder, baking soda, and salt.
In another bowl, mix buttermilk, vegetable oil, and beaten eggs.
Pour the wet ingredients into the dry ingredients and stir until just combined.
Fold in the chopped plums.
Pour the batter into the prepared loaf pan.
Bake for 60 minutes or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.