In On the Underground, the players build the Underground lines in London or the U-Bahn lines in Berlin. Each player controls 2-4 different lines, depending on the number of players.
On each turn, four destination cards are available, corresponding to stations on the map. You can take up to four actions; an action is either building track by placing one of your track tokens on the board or taking a branch token. A player may use two branch tokens to branch out of an existing line (whereas normally lines can be extended only at the endpoints).
After each player's turn, a passenger token is moved along players' lines, avoiding walking as much as possible, to reach one or two destinations determined at the beginning of the turn. The destination cards corresponding to the visited stations are then replaced by new ones, then the next player takes their turn.
Players score points in two ways:
- By building track and connecting their lines to various types of stations, by building a circular line (in London), or at the end of the game if they have collected tiles from specific landmark stations (in Berlin).
- By having the passenger use their lines when moving.
After all destination cards have been drawn and all players have taken the same number of turns, the game ends.
