This article was updated on October 17 with the latest information from the publisher.
Cities: Skylines was the antidote to 2013's bungled always-online SimCity reboot. It was a regular old offline, singleplayer game with mod support: hallelujah. From the sounds of it, Cities: Skylines 2 will be just as moddable as the original, but there will be one notable change: You won't be getting your Cities: Skylines 2 mods on Steam Workshop.
In a post on its forums today, Paradox said that the official mod distribution channel for Cities: Skylines will be Paradox Mods, its custom cross-platform mod library. In a related FAQ, it said that Steam Workshop won't be supported.
It's a little disappointing, because Steam Workshop is a pretty darn convenient way to find and install mods, but the new platform does have the advantage of allowing Paradox to offer asset mods to console players as well as PC players. The publisher also says that using its own platform from the start allows it to create an "integrated in-game experience" around mods, so maybe it'll be just as convenient as Steam Workshop.
Over a hundred mods for the original Cities: Skylines are currently available on Paradox Mods, although tens of thousands are available on Steam Workshop, so it's yet to be seen how the platform will handle sorting a full library of mods for the city builder (which on PC should include a lot more than just additional assets). Other Paradox games do have bigger Paradox Mods libraries: There are over 30,000 Hearts of Iron 4 mods on the platform, for instance.
"The version [of Paradox Mods] made for Cities: Skylines 1 was made so that a few hand-selected assets could be used on Xbox, and the idea for Cities: Skylines2 is much grander," Paradox wrote in a follow-up FAQ. "We want to make the creation, uploading, sharing, and downloading experience as smooth as possible for a community that enjoys modding as much as you do."
Mod updates will download and install when the game is launched, and the system will support mod grouping according to dependencies and include a rating system. Paradox also says it has no plans for "paid mods."
The Cities: Skylines 2 mod tools and its Paradox Mods integration won't quite be ready in time for its October 24 release date, though. The "in-game editor" is in beta, Paradox said, and "will launch shortly after release."
"While we look forward to unleashing the power of creative modification to all of you, in preparation, we are collaborating with a talented group of creators working behind the scenes—ensuring you'll have amazing mods to dive into on the launch of the mods platform," said the publisher.
In the same post, Paradox also warned players to expect performance issues when Cities: Skylines 2 launches next week. Tons of games struggle with poor performance at launch, but I can't think of another example of a developer so bluntly advising prospective players that, yeah, things are going to be rough on day one. (Usually, they wait until a "mostly negative" Steam reviews average emerges before penning a "sorry, sorry, we'll fix it" letter, so although it's not exactly good news, I suppose I have to appreciate Paradox for giving us a heads-up.)