According to EA, it isn't possible to play SimCity
offline; yet, AzzerUK
has proved them wrong. This modder has been able to mod the game in order to play it, without any time restriction, offline.
This modder has accessed the game's debug mode, and played SimCity offline, without getting any error whatsoever. The only downside of this is that, in this mode, players aren't able to save or load data; therefore, in order to save or load data, it would be necessary to go to the online mode of the game.
Yet, every changes done while playing offline remain on the servers, when/if the player goes online. So, if someone wants to play it offline, and alter highway routes, for example, and then go online, save and exit the game, those changes to the highways are kept in the server.
AzzerUK reported on Reddit
"with a little bit of package editing within SimCity and a little playing about in the code, it's possible to enable debug mode....you can edit the highways ANYWHERE - even outside of your city boundary..."
This brings up the question Why don't EA Maxis' want to let users play offline if it is totally possible to do so?