ATL has two passenger terminals. The Domestic Terminal has a North and a South side. The International Terminal is a separate building on Maynard H. Jackson Jr. Boulevard. Guests report a free bus between them outside security, which we could not confirm on ATL's pages.
Airlines
ATL's site lists the carriers but not which terminal each one uses. Delta and most domestic airlines use the Domestic Terminal, and most foreign airlines use the International Terminal, per third-party guides. Check your ticket.
What it means for hotels
The SkyTrain and the hotel shuttles start at the Domestic Terminal. If you land at the International Terminal, you take the terminal-to-terminal bus first. Guests report 10 to 15 minutes, which we could not confirm.