While "LAN play" in the traditional offline sense is not available, you can play locally by using the standard online multiplayer features. Internet Connectivity
Anno 1800 offers LAN-style connectivity, but not traditional offline LAN. If you and your friends are in the same house or using a virtual LAN tool, it provides a more stable experience than internet matchmaking—just don’t unplug the router. anno 1800 lan multiplayer link
Adjust settings like map size, starting capital, and AI opponents, then select Start Game 3. Joining a Session Via Invite: While "LAN play" in the traditional offline sense