: Manually forward UDP Port 18000 in your router to your PC’s local IP address. Note that routers typically only allow forwarding a specific port to one device, which can cause issues if multiple people are on the same local network. Resolving Desyncs (LR40 Error)
Ensure that both the Anno1800.exe application and the UbisoftConnect.exe launcher have explicit access permissions.
Click on the left panel. Click Change settings (requires administrator privileges). Scroll down to find Anno 1800 and Ubisoft Connect .
Under the tab, click Settings within the Performance block. anno 1800 lan multiplayer fixed
: A frequent issue involves "Out of Sync" errors. A known community fix involves all participating players deleting the contents of the desync folder located in the Windows user directory for Anno 1800 before restarting the session.
Ensure both Anno 1800 and Ubisoft Connect are allowed through your Windows Firewall. For local play, verify both PCs are on the same subnet (e.g., both 192.168.1.x) and ideally using IPv4 rather than IPv6. Resolving Synchronization & Lag
Ensure both Anno1800.exe and your VPN software are allowed through the Windows Defender Firewall. 4. Hardware and Performance Fixes : Manually forward UDP Port 18000 in your
A major update was released to resolve severe desync issues on PC. This fix stabilized sessions that previously crashed every few hours.
Have you tested Anno 1800 LAN on a school network or at a large event? Share your experience in the comments. For detailed firewall rules and the latest LAN Launcher builds, check the r/anno subreddit’s pinned “Multiplayer Tech” thread.
Anno 1800 does not offer a traditional offline LAN mode, but with the configurations and troubleshooting steps outlined in this guide, you can achieve a seamless "LAN-like" multiplayer experience with friends in the same local network. The key takeaways are: Click on the left panel
Anno 1800 relies on specific network ports to transmit game data between players. If your router blocks these ports, LAN connections will fail. Access your router's gateway page to open the following ports:
While Anno 1800 lacks a dedicated offline LAN button, the —using stable, high-speed internet to connect via the Ubisoft Connect interface—is the most reliable way to play in 2026. For those wanting to eliminate internet reliance entirely, a tool like Radmin VPN provides the best "fixed" solution, making the game think you are on a stable local network.
As of 2026, Anno 1800 does feature a native, "offline LAN" button in its menu. The game’s architecture relies on Ubisoft Connect servers to authenticate players and initiate multiplayer sessions, even if those players are in the same room.
Ensure all players are utilizing the same API. If one player uses DirectX 11 and another uses DirectX 12, desync frequencies increase dramatically. Switching everyone to DirectX 11 offers the highest stability for multiplayer. Clear the Game Cache