Terraforming Mars Tile Placement Rules: Cities, Greenery, Oceans & Bonuses
Terraforming Mars tile placement has several separate rules depending on whether you place a city, greenery, ocean or special tile.
Printed placement bonuses
When you place a tile on a hex with printed resources or cards, gain that printed placement bonus immediately.
Ocean adjacency bonus
Whenever you place a tile next to one or more ocean tiles, gain 2 M€ for each adjacent ocean. This bonus applies to normal tile placements unless an effect specifically says otherwise.
City placement
A city generally cannot be placed adjacent to another city. Some project cards create exceptions or specify a reserved location.
Greenery placement
When you place greenery, it must be adjacent to another tile you own if possible. If you cannot legally place it adjacent to one of your own tiles, you may place it on another legal non-ocean hex.
After placing greenery, raise oxygen one step if oxygen is not already at maximum.
Ocean placement
Ocean tiles go only on spaces reserved for oceans. When you place an ocean, increase your TR by 1 if the ocean global parameter is not already complete.
Special tiles
Special project cards tell you what type of tile to place and may override normal placement restrictions. Follow the card text when it conflicts with the general rule.
Who owns a tile?
Cities, greeneries and many special tiles are marked with your player marker when you own them. Ocean tiles are neutral and are not owned by the player who placed them.
Related guides
Official source
Placement rules checked September 2026.