A turn is the period of time during which a player may play and buy cards, and then clean-up for their next turn. Almost all gameplay happens during a turn. Players alternate taking turns until the game ends. If a previous game has been played, the player with the fewest points of that game takes the first turn in the next one; otherwise, the first player should be determined randomly.
 Turn phases
At the start of their turn, a player is given 1 Action and 1 Buy. A player may accumulate more of these as their turn progresses.
- Action phase (A): The current player may play Action cards as long as they have Actions remaining.
- Buy phase (B): The current player may play any number of Treasures from their hand, and then may buy cards or Events as long as they have Buys remaining, and enough resources remaining to buy them.
- Night phase (N): The current player may play any number of Night cards from their hand. This phase only happens in games using Night cards.
- Clean-up phase (C): The current player discards all cards in their hand, and all cards in play other than Duration cards (and associated Throne Room variants and Command variants) that have not yet finished tracking effects are discarded, including those played by other players. Then the current player draws 5 new cards from their deck, and ends their turn.
Certain cards or card-shaped things have effects that can alter the sequence of phases, or change what happens in them.
 Turn count
It is useful to keep track of how many turns have been played by each player, for a number of reasons:
- If more than one player has the highest score at the end of the game, the player who took the fewest turns wins. If they took the same number of turns, the game remains a tie. This is partly to remedy first player turn advantage.
- In strategic discussions, the effectiveness of a strategy is often determined by the average number of turns it takes for it to gain four Provinces. A pure Big Money strategy typically does this in 16 turns; adding one or two copies of certain Action cards, such as Smithy or Jack of all Trades, can drop this to anywhere from 14 to 11 turns. This metric is less useful in engine or slog mirrors; the former is more concerned with gaining all (or most) of the Provinces in one or two turns after building up their deck, while the latter is slowed down by powerful Attacks.
 Turn order
Whenever an effect happens to more than one player, or multiple effects involving different players try to resolve at the same time, they are resolved in turn order, starting with the player whose turn it is (or the player who last took a turn). This is important particularly with regards to gaining cards: for example, if a player plays Witch, and there's only one Curse left, only the player next in turn order gains a Curse.
 Extra turns
Three cards (Outpost, Possession and Voyage) and five additional card-shaped things (Mission, Fleet, Seize the Day, Island Folk, and Journey) allow a player to take more turns than normal, each with its own penalties or restrictions. These extra turns do not add to a player's turn count, and are not used in breaking ties.
Extra turns happen in turn order—if a player plays Outpost and Possession on their turn, the Outpost turn happens first. The Possession turn is not their turn, but the turn of the next player; they are simply controlling what happens.
In 2023, Donald X. introduced errata to prevent players from getting more than one extra turn at a time in most cases.
 Skip turns
One card, Lich, can cause you to skip turns. Skipping a turn means that the next time you would take a turn, you don't; nothing happens for that turn: no "start of turn" abilities, no phases. Play continues with the player to your left as usual.
- You can skip an extra turn, like one from Voyage.
- Skipped turns still count for the tiebreaker however they would have if taken.
- Abilities that refer to your "last turn" or "next turn" skip the skipped turn as well. If you play a Caravan and skip a turn, the Caravan will draw you a card on the next turn you actually take; if someone plays a Smugglers they'll gain a copy of a card you gained on the last turn you actually had.
 Between turns
A few decisions, usually deciding which of multiple extra turns should occur first, take place between turns. In those cases, the player who took the last turn is considered to be in control, and is the one who makes such decisions. It does not matter if that player was Possessed on the previous turn; it is still their decision.
The original versions of the Event Donate and the Landmark Mountain Pass, from Empires, resolve between turns (so that Possession is not in effect when decisions are made), but revisions of these cards have those abilities take place during the turn.