Preheat oven to 375 degrees. Spray a loaf pan with cooking spray and set aside.
In a large mixing bowl, add the flour, baking powder, baking soda, caster sugar, dark brown sugar and sea salt. Whisk to combine the dry ingredients.
Add the kombucha and whisk to combine.
Pour into the prepared loaf pan and bake for 45 minutes, until the bread is lightly browned.
Let cool 10 minutes before serving.