For the 2009 Mazda Mazda3, the low-beam bulb depends on the headlight system: use H7 with halogen headlights or D2S with HID headlights. The high-beam fitment is 9005.
Check the original fog-light bulb before ordering, as the supplied fitment lists two options: 9006 LED or H11 LED. The front turn signal, parking light, and front side marker use 1157A.
Other notable exterior bulb sizes include 7440 for the reverse light, 7443R for the brake and tail lights, 921 for the center stop light, 7440A for the rear turn signal, and 2825 for the license plate light. Interior lighting uses DE3175 for the dome light and 2825 for the map light. For the trunk light, compare the original bulb to determine whether the correct option is 2825 or DE3022.