It is possible to play SimCity offline indefinitely, according to a video of a modded version of the game posted to YouTube.
Modder UKAzzer uploaded the video which shows him disabling the game's disconnection timer. Previous tests confirmed that SimCity will kick a user from the game after roughly 20 minutes of offline play; however, while its impact on a number of features in the game means this offline mode is still not ideal, the video demonstrates some form of unlimited offline play is indeed possible.
According to the modder's initial posts on Reddit, while the game can be played indefinitely without connecting online, it is not possible to save the game without reconnecting the game and cross-region play is also impossible.
"Works a treat! No region stuff of course, and you have to stay in your city, and there's no way to save the city unless you reconnect... but it's something," he writes. "The '20 minutes' Kotaku reported on being able to stay playing for before being kicked to main menu for no connection is a random figure the devs put in, very odd."
Regarding how difficult it would be to completely remove the online aspects of the game, he goes on to state he is unsure.
"Hmm, don't know about totally, but I'm experimenting with hacking in ways to spoof it into 'claiming' a city without sending that info to the server, loading that city data up from local data, and enabling editing, so you can edit a city and pick a region square all offline," he says. "Still don't think I can find any simple way to SAVE it yet, but it'll be a start. Whether I take it any further than that, or leave that to the real hardcore coders/hackers with more time on their hands, I don't know."
Beyond this, the modder is shown accessing the game's debug mode. In doing so he is able to edit highways that connect cities together. According to the modder's post, "You can edit the highways ANYWHERE — even outside of your city boundary, and even if you quit the game and log back in later, it's all saved safely on the server.
"This shows that highway editing will be easily possible, AND that editing outside of the artificially small city boundaries should be very viable too."
The mod also adjusts the apparently "fluffed population count" to show the actual population count in cities, something users have complained about since the game launched.
Maxis general manager Lucy Bradshaw previously told Polygon it is not possible to make the game an offline title without "significant" changes.
"We offload a significant amount of the calculations to our servers so that the computations are off the local PCs and are moved into the cloud," she said. "It wouldn't be possible to make the game offline without a significant amount of engineering work by our team."
Maxis announced earlier in the month it has "no intentions" off making SimCity available for offline play.
Polygon has reached out to Maxis for a breakdown of what specific calculations are being conducted by servers and which are handled locally. We have also reached out to the modder for an explanation of how difficult it is to access the offline mode.