Catan Trading & Port Rules: 4:1, 3:1 and 2:1 Explained
Catan has two main kinds of trading: domestic trade with other players and maritime trade with the bank. Ports improve your maritime rate.
Domestic trading
On your turn, you may negotiate trades with the other players. Only the active player can trade with opponents; two non-active players cannot trade directly with each other during someone else’s turn.
Can players give cards away?
A domestic trade must be a trade of resource cards. The rules do not treat simply gifting a resource for nothing as a normal trade.
Standard bank trade: 4:1
Without a port, you may return 4 resource cards of the same type to the supply and take 1 resource card of your choice.
Generic port: 3:1
If you have a settlement or city on a generic 3:1 harbor, you may trade 3 matching resources for 1 resource of your choice.
Specific port: 2:1
A specific harbor shows one resource type. If you have a settlement or city there, you may trade 2 cards of that resource for 1 resource of your choice.
Can you mix resources for a port trade?
No. A maritime trade uses matching cards of the required type. A 3:1 trade means three of one resource, not three different resources.
Do you need a road connected to a port?
You need a settlement or city on the harbor intersection to use that harbor’s rate. Merely running a road past the coast does not activate it.
Can you use a port immediately after building on it?
Check the exact edition/rule sequence you are using. Current CATAN materials support trading and building within your turn according to the current turn structure, while older editions and variants can phrase ordering differently. The harbor itself becomes usable once you legally control it.
Related Catan guides
Official source
Rules checked September 2026.