Cities: Skylines II Editor Early Access Opens to Mod Creators

Colossal Order is inviting modders, map makers and asset creators to apply for early access to the Cities: Skylines II Editor, giving selected creators an opportunity to test the unfinished tools before their planned public release in early 2024. The developer is also preparing a larger December patch to address performance and simulation problems following the game’s October launch.

In the November 27 Word of the Week developer update, Colossal Order CEO Mariina Hallikainen explained that early-access participants would receive access to the Editor for several weeks before its wider release. The aim is to gather feedback, test existing creations and identify problems with the modding workflow.

The announcement follows the earlier decision to launch Cities: Skylines II without official mod support, with Paradox Mods intended to replace Steam Workshop as the sequel’s official mod distribution platform.

However, some community creators have already discovered an unfinished Editor included in the game’s release build. Despite the absence of officially released tools, modders have managed to create custom maps and code modifications.

Colossal Order welcomed that progress but warned against relying on the unfinished Editor for permanent projects.

Changes to the way maps are saved could prevent existing creations from working with later versions of the game. Water placement and landscaping tools are also being revised, potentially breaking community-made tools that interact with those systems.

That warning is particularly important for anyone investing substantial time in a custom map. A project created with the hidden Editor might need additional work, or even rebuilding, once the official tools become available.

The developer has also updated its modding wiki with more information about creating custom assets. One notable omission is detailed guidance for level-of-detail models, which Colossal Order hopes to handle through an automated system. Creators would still have the option of producing their own LOD models where necessary.

I think the most useful part of this announcement is the warning about map compatibility. Early access gives creators an opportunity to understand the tools, but anyone developing a detailed map needs to recognise that the underlying file formats and editing systems are still changing.

Alongside the Editor, Colossal Order outlined work on the game’s next major patch.

The studio is reducing the rendering cost of geometry to improve performance and investigating several simulation problems, including mail delivery, resource exports, statistics and achievements that fail to unlock. A bug involving a taxi becoming stuck because of a child passenger is also being addressed.

These changes follow the earlier hotfix 1.0.12f1 performance and economy adjustments, although the developer has not confirmed that every outstanding problem will be resolved in December.

Colossal Order expects to release the larger patch before its holiday break, scheduled to begin in approximately three weeks. No further patches are planned during the break, and developer responses will be limited until work resumes.

For mod creators, the immediate opportunity is early access to tools that are still changing. For other PC players, the next milestone is December’s planned update, with further performance improvements and gameplay fixes intended before the end of 2023.

Later Update: The first public Cities: Skylines II Modding Beta launched alongside patch 1.1.0f1. Paradox’s official announcement confirmed that players could create and share map and code mods through Paradox Mods, while asset modding tools remained unavailable. The release fulfilled part of the November early-access plan, although the original early-2024 target resulted in a March beta rather than a complete Editor release.