On Mars is played over several rounds, each consisting of two phases - the Colonization Phase ​and the Shuttle Phase​.

During the Colonization Phase, each player takes a turn during which they take actions. The available actions depend on the side of the board they are on. If you are in orbit, you can take blueprints, buy and develop technologies, and take supplies from the Warehouse. If you are on the surface of the planet, you can construct buildings with your bots, upgrade these buildings using blueprints, take scientists and new contracts, welcome new ships, and explore the planet’s surface with your rover. In the Shuttle Phase, players may travel between the colony and the Space Station in orbit.