The Seafarers of Catan (German: Die Seefahrer von Catan) is an expansion of the board game Settlers of Catan for three to four players (five to six player play is also possible with both of the respective five to six player expansions). The main feature of this expansion is the addition of ships to the game, allowing play between multiple islands. The expansion also provides numerous scenarios, some of which have custom rules.
The Seafarers rules and scenarios are also, for the most part, compatible with Cities and Knights of Catan and Catan: Traders & Barbarians. The concepts introduced in Seafarers were part of designer Klaus Teuber's original design for Settlers. Seafarers introduces the concept of ships, which serve as roads over water or along the coast.
Each ship costs one lumber and one wool to create (lumber for the hull and wool for the sails). A settlement must first be built before a player can switch from building roads to building ships, or vice versa. Thus, a chain of ships is always anchored at a settlement on the coast.
A shipping line that is not anchored at both ends by different settlements can also move the last ship at the open end, although this can only be done once per turn and may not be done with any ships that were created on the same turn.