Free City Building Games: PC and Open-Source Picks

The short answer

OpenTTD and Simutrans are free open-source PC games built around transport networks and city growth. Unknown Horizons is an open-source economy and settlement project. Virtual City Playground is free-to-play with optional in-app purchases. Combolands is paid, and its launch removed the separate free demo.

Side-by-side

Free, open-source, free-to-play and paid

The download price is only one part of the choice. Check the building focus and monetization model too.

Game	Core interaction	Run structure	Best fit
OpenTTD	Connect industries and cities with road, rail, water and air transport networks.	Large procedural maps support long transport economies alone or with friends.	Free open-source network building with deep logistics.
Simutrans	Move passengers, mail and goods while transport activity influences city growth.	Customizable maps and graphics packages support solo, public, private or LAN play.	Free open-source transport simulation with extensive configuration.
Unknown Horizons	Develop an isometric settlement through economy, trade and real-time strategy systems.	An open-source project focused on growing a colony rather than short roguelike runs.	Players seeking a free economy-first settlement game.
Virtual City Playground	Grow a colorful metropolis, produce goods and manage transit at a relaxed pace.	Free-to-play progression with optional bonuses sold through in-app purchases.	Players who accept a F2P model instead of an open-source game.
Combolands	Place building cards on islands and combine nearby effects into scoring chains.	Paid single-player runs designed around roughly 30 minutes; the former demo is unavailable.	Players willing to pay for compact roguelike city-building runs.

Start by separating four meanings of “free”

An open-source game, a free-to-play store game and a demo can all appear in the same search result, but they make different promises. Open-source projects publish software under a license and do not depend on an upfront purchase. Free-to-play games remove the entry price but may sell optional bonuses. A demo is a limited sample whose availability can end. A paid game should not be described as free simply because an old demo or unofficial download remains indexed.

OpenTTD: free logistics on very large maps

OpenTTD's official page calls it free and open-source software. The game is primarily a transport business simulation: you connect industries and cities across procedural maps, move passengers and cargo, and expand capacity as towns grow. It suits players who enjoy logistics more than hand-placing every house.

Simutrans: transport decisions shape city growth

Simutrans is also described as freeware and open source. Its focus is establishing a transport company, interconnecting cities and industries, and watching transport activity influence growth. It offers multiple graphics packages and supports public, private and LAN multiplayer, making it a strong free option when configuration and network design matter.

Unknown Horizons: an open-source settlement economy

The Unknown Horizons project describes a 2D real-time strategy simulation with an emphasis on economy and city building. It is the closest of these open-source choices to an economy-led settlement game, but the project is also in a technology transition toward Godot. Read the current project status before assuming the same release cadence as a commercial Steam game.

Virtual City Playground: free entry with optional purchases

Virtual City Playground explicitly says it is free to play and that optional bonuses can be unlocked through in-app purchases. That is not automatically bad, but it is a different budget decision from OpenTTD or Simutrans. Choose it when a relaxed, colorful metropolis and F2P progression sound preferable to an open-source simulation.

Combolands is not a free city building game

Combolands is a paid Steam game. Its separate demo listing stopped resolving after the August 24 launch, and the live store no longer offers that demo. Use the release and price guide for the current official offer, and avoid unofficial “free download” or APK pages. The platform guide explains why Windows is the only confirmed platform.

Quick answers

Frequently asked questions

What city building games are completely free?

OpenTTD and Simutrans are free open-source transport and city-growth simulations. Unknown Horizons is an open-source economy and city-building strategy game. These are different from free-to-play games that may sell optional items.

Are there free city building games on Steam?

Yes. OpenTTD and Simutrans can be added and played for free on Steam. Virtual City Playground is free-to-play but includes optional in-app purchases.

Is Combolands free?

No. Combolands is a paid Windows game on Steam. Its separate free demo was removed after launch, so sites offering an unofficial free Combolands download are not an official source.

What is the difference between free and free-to-play?

A genuinely free open-source game can be downloaded and used without buying gameplay content. A free-to-play game has no upfront price but may offer optional purchases. A demo is only a limited sample of a paid game.

Which free city builder supports multiplayer?

OpenTTD supports playing alone or with friends, and Simutrans supports public, private and LAN multiplayer. Check the multiplayer guide for mode details and paid alternatives.