Ubisoft’s previousily stated that Tom Clancy’s Rainbow Six Siege won’t have single player, but you can play solo or co-op against enemy AI. Apparently, that can’t be done offline.
A statement released by Ubisoft at the time said:
“The game supports solo play when playing Terrorist Hunt offline & online and we will provide further details on single-player content in the near future.”
However, players who already have the game report not being able to play the Terrorist Hunt mode offline. Ubisoft’s Community Manager responded by saying that “an internet connection is required to play Terrorist Hunt mode,” and that only “situations and custom multiplayer matches are available offline.”
He said that he will pass this suggestion to the development team, but actually, it should be there already like they promised. Tom Clancy’s Rainbow Six Siege released on December 1 for PS4, Xbox One and PC.