SimCity's Single-Player Offline Mode Now Live
Back in January, Maxis (finally) announced that SimCity would be getting an offline mode, ditching the much-criticized Always-On requirement. A later blog post explained how it was not "as simple as flipping a switch," due to so many components and features built with server access in mind; and in fact, the team had been working on the offline mode since August 2013. Yesterday, a little over a year since launch, SimCity's offline mode is finally live.
As you can see in the video and screenshot below, the main menu for the game has been updated to accommodate two options, "Single-Player" and "Multiplayer". As previously stated, players can switch back and forth between the two, so you're never stuck in one mode or the other. Once you choose Single-Player, you can then launch the game without an Internet connection and never need to go online again if you don't want to – great for anyone who wants to play some SimCity during travels, or who is serving our country and stationed overseas.
In the new Single-Player mode, players are able to turn off AutoSave and even save multiple versions of your regions with the new "Save As" option. However, in order to "keep the competitive aspects of the Online game intact," you cannot transfer saved regions between modes. The good news is that no matter what mode you play, you have access to all DLC you own and any free content Maxis has given away.
Aside from being able to play without an Internet connection, the other major benefit of offline play is the official support of modding, as even the most extreme modding won't harm "the integrity of the Online game." The only things you miss out on by playing Single-Player are "Multiplayer, SimCity World, Leaderboards, Achievements, dynamic pricing of resources in the Global Market and Cloud Saves." A small price to pay for freedom of choice.
Source: SimCity Blog