Free Alternatives to Cities: Skylines & Transport Tycoon
Short answer
OpenTTD is the best free alternative to Cities: Skylines and Transport Tycoon: a free, open-source transport network simulation in continuous development since 2004, with multiplayer and a vast official add-on library.
Network-building simulation — routes, logistics, watching a system you designed slowly come to life — has one outstanding free option, and it has been refined continuously for over two decades.
Our pick: OpenTTD
OpenTTD is an open-source rebuild of Transport Tycoon Deluxe with 25 years of improvements: enormous maps, multiplayer, and a colossal library of add-on content through its in-game download service.
How it differs from Cities: Skylines: Transport networks rather than city zoning. You do not paint residential districts; you connect the towns that already exist and grow them through service.
All free Cities: Skylines alternatives compared
OpenTTD
OpenTTD is an open-source rebuild of Transport Tycoon Deluxe with 25 years of improvements: enormous maps, multiplayer, and a colossal library of add-on content through its in-game download service.
The difference: Transport networks rather than city zoning. You do not paint residential districts; you connect the towns that already exist and grow them through service.
OpenTTD clears all five: free with no monetisation, exceptionally complete after two decades of refinement, still actively developed, better than the commercial game it descends from, and open-source so it cannot be lost.
Luanti
If the appeal is building a settlement from nothing, Luanti's voxel sandbox gives you unlimited terrain and hundreds of building-focused game modes.
The difference: First-person voxel construction, not top-down management. No simulation of citizens or economy.
Luanti clears all five: free with no monetisation, a mature and stable engine, actively developed, genuinely excellent as a platform, and open-source so it cannot be taken away.
Mindustry
Mindustry is the logistics half of the appeal distilled: conveyor networks, resource chains and throughput optimisation, with combat pressure on top.
The difference: Factory logistics rather than civic simulation, and it is an actively hostile environment — things attack your network.
Mindustry clears all five: free with no monetisation on desktop, complete and heavily content-rich, actively developed, easily good enough to sell, and open-source under GPL-3.0.
Questions
What is the best free alternative to Cities: Skylines?
OpenTTD is the best free alternative to Cities: Skylines and Transport Tycoon: a free, open-source transport network simulation in continuous development since 2004, with multiplayer and a vast official add-on library.
Are these Cities: Skylines alternatives really free?
Yes. Every game listed here is free with no trial, no paywalled content and no pay-to-win purchases. All are open-source, which means they cannot be delisted or shut down. Each has been assessed against PlayBound's five published criteria.
Do I need to pay for multiplayer in these Cities: Skylines alternatives?
No. None of these games charge for multiplayer. Public servers are community-run and free to join, and there is no subscription of any kind.
How is OpenTTD different from Cities: Skylines?
Transport networks rather than city zoning. You do not paint residential districts; you connect the towns that already exist and grow them through service.
How is Luanti different from Cities: Skylines?
First-person voxel construction, not top-down management. No simulation of citizens or economy.
How is Mindustry different from Cities: Skylines?
Factory logistics rather than civic simulation, and it is an actively hostile environment — things attack your network.
Every game here has been assessed against the PlayBound Bar — five published criteria for whether a free game is actually worth your time.