In 2026, the travel time between the International Terminal (Concourse F/Terminal 5) and the Domestic Terminal (Terminal 1) at Hartsfield-Jackson Atlanta International Airport (ATL) depends on whether you are "landside" or "airside." If you have already cleared security, you should use the Plane Train, which runs 24/7 on a 3-mile underground loop. The train journey itself between the two furthest points takes about 12 to 15 minutes, with departures every 2 minutes. However, when you factor in the time to walk from your gate to the train station and then from the station to your next gate, you should budget at least 25 to 30 minutes. If you are "landside" (outside security) and need to move between the Domestic and International buildings, you must take the free terminal-to-terminal shuttle bus, which travels on the perimeter road. This bus ride takes approximately 12 to 15 minutes, but with waiting times and loading, the total transition can take 30+ minutes. It is a crucial peer-to-peer tip to know that you cannot walk between the two main terminal buildings landside; you must use the shuttle or the SkyTrain to the Rental Car Center to switch.