The Atlanta International Airport is located at 2600 Maynard H. Jackson Jr. Blvd., and handles all international flights separate from the domestic terminal building.
To get there on MARTA, riders should take any southbound train to the Airport Station, which is the domestic terminal. Exit the train and go down the escalator/steps to exit the station. Turn left after going through the fare gate to enter the baggage claim area. Immediately turn left again and exit out of the building, making sure to follow signs to Ground Transportation. A bus is available just outside the domestic airport that takes passengers to the international terminal. The shuttles come in a variety of shapes and sizes, so the bus may look like a stage coach/tour bus. Signage should be available to help identify the stop for the bus.
If you are arriving at the international airport, again, follow signs to ground transportation/domestic airport shuttle. MARTA is just inside the airport once you arrive at the domestic terminal and there are clear signs marking the station entrance.
For more information, see:
Tips for Riding MARTA to/from the Airport
MARTA Schedules to the Atlanta Airport
Atlanta Airport Parking vs. MARTA Long-term Parking