The Situation:  The ticket for your itinerary that connects through Atlanta on to an international destination shows that you arrive in the Domestic North/South Terminal and depart from the International Terminal. You are flying all on one ticket, and either using the same airline for both legs or using codeshares. For example, you are flying Delta to Atlanta, then Air France (a DL codeshare) to Paris. How do you get from one to the other?

First, these tickets are somewhat misleading for 2 reasons:

1)     The term "Terminal" refers to the check-in and baggage claim area, which you will not need since you are on one ticket and do not need to re-check luggage.  Planes do not fly into either terminal, so you are not actually flying into the Domestic North Terminal. That is just where your airline’s main check in desks are located. Planes land at the "Concourses." More on that to follow.

2)     The “International Terminal” is the separate building where passengers arrive and check in for international flights, but it is adjacent to Concourse F. Many refer to Concourse F as the “International Concourse” but in reality international flights can arrive in Concourse E or F (or others if the flights are Pre-Clear), and can depart from any concourse.

For these reasons, you should ignore the “Domestic North/South Terminal” and “International Terminal” designations on your ticket. This is merely a placeholder until the actual gate assignment is made. What matters is where you land (Concourse T, A, B, C, D, E, or F) and where you need to go to reach your connecting flight (again, Concourse T, A, B, C, D, E, or F). The airport’s own diagram illustrates this best:

http://www.delta.com/content/www/en_U...

Once you arrive in Atlanta, (and clear customs & immigration if arriving from abroad) check the overhead screens or your carrier's app to determine which Gate (numbered) and Concourse (lettered) your next flight will depart from. For example, A39 is Gate 39 on the A Concourse. Even if this information is printed on your boarding pass or was given to you when you checked in for your first flight, it is important to confirm this once you arrive in Atlanta, as gate assignments can and frequently do change. If you are already on that Concourse, just walk to the next Gate. If you are not, follow the signs towards the center of the Concourse, which direct you to the Plane Train, which you will use to reach the other Concourses.  The Plane Train runs to all Concourses, runs about every 2 minutes, and takes about 3-4 minutes to run from F to T.

http://en.wikipedia.org/wiki/The_Plan...

Bear in mind that international flights officially start boarding 50-60 minutes before take-off, and so what seems like a comfortable layover may not be as long as you think. Take that into account when budgeting your time. Happy Travels!