Getting Started with Crusader Kings III Modding

Crusader Kings III modding is one of the most accessible entry points into Paradox modding generally — the data files are exposed as readable scripts, the Workshop catalogue is enormous, and the launcher handles load order. This guide walks the standard install on the current CK3 release.

Step 1 — Subscribe through Workshop

Open the CK3 Workshop. Subscribe to mods. Steam downloads them.

Three popular first picks for vanilla-flavoured modded play:

• Sinews of War — adds combat depth without changing the strategic layer.
• Better Battles — visual improvements to battle screens.
• More Bookmarks+ — adds historically-grounded scenario start dates the base game omits.

For a total conversion (alternative setting):

• A Game of Thrones (AGOT) — the canonical Game of Thrones mod for CK3. Has its own load order, its own bookmarks, hundreds of additional events.
• Fallen Eagle: The Bleeding Sun — Late Roman Empire setting (predates vanilla CK3's start date).

Step 2 — Configure load order in the Paradox Launcher

The Paradox Launcher (which CK3 uses) has a Playsets tab. Each playset is a saved mod configuration with a specific load order.

Drag mods within a playset to set load order. Later-loaded mods override earlier ones — this is the cardinal rule of Paradox modding. Compatibility patches go after the mods they patch.

Save the playset with a descriptive name. You can have multiple playsets (vanilla-flavoured, AGOT, Fallen Eagle, etc.) and switch between them.

Step 3 — Launch with the playset

The launcher's Play button uses the active playset's mod list. CK3 launches with those mods loaded.

The main menu shows a "Mods active" indicator. Mid-game, the in-game UI is mostly unchanged but the content reflects the mod set.

Step 4 — Achievements and Ironman

Achievements require the vanilla checksum. Any mod that changes game data invalidates the checksum and disables achievements.

Some mods declare themselves "Ironman-compatible" (typically UI-only or cosmetic mods). The launcher shows this on each mod's listing.

For most modded playthroughs, accept that achievements are off. Workshop badges of "Ironman-compatible" are the exception.

Step 5 — DLC compatibility

CK3 has many DLCs (Royal Court, Tours and Tournaments, Roads to Power, etc.). Each adds new content the base game lacks.

Mods may:

• Require specific DLCs to function (e.g. court-related mods need Royal Court).
• Conflict with specific DLCs (e.g. an event mod that overrides a DLC's content).
• Be neutral to DLC presence.

Read the mod's compatibility notes. Most major mods list supported DLCs explicitly.

Common gotchas

• Save game won't load. Most often: changed mod list since the save was made. Re-enable the original mods, save fresh, then reorganise.
• Mod conflict warnings in launcher. The launcher detects mods that touch the same files. Usually safe but worth checking each conflict's resolution (which mod's version wins).
• Total conversion expectations. Installing AGOT or Fallen Eagle is more than a mod — they're effectively different games. Read each TC's getting-started documentation before launching.
• Game crashes on launch. Usually a malformed script in a mod. The CK3 error log (in user documents) shows which file failed to parse. CK3 Tiger (community linter) catches most before they crash.
• Newer DLC content doesn't appear with mod. The mod is older than the DLC. Look for an updated mod version or compatibility patch.

If you've modded EU4, HoI IV, or Stellaris, the patterns transfer directly — same launcher, same playset workflow, same script-data approach.