Does the Robber Block Port Trading in Catan?
You're mid-game, someone rolls a 7, and the robber lands on a hex that connects to your port. Now you want to use that port for a 2:1 trade. Can you?
What the Robber Actually Does
According to the official Catan rules, the robber has exactly two effects:
Blocks Production
When the number on the robber's hex is rolled, no one with a settlement or city there gets resources.
Steal One Resource
The player who moved the robber takes one random card from any player adjacent to the robber's new hex.
Why This Confusion Exists
The confusion comes from the physical board layout. Ports sit at the edge of hexes, and when the robber is placed on a hex near a port, it looks like it should block the port.
But mechanically, ports have no connection to hex tiles. A port is linked to two specific intersection points (where you build settlements), not to any hex.
What About the Pirate in Seafarers?
If you're playing Catan: Seafarers, the pirate can interfere with shipping routes — but even the pirate doesn't block port trading. The pirate prevents you from building or moving ships adjacent to its hex. Ports remain unaffected.