The official website for The Settlers of Catan

Question about Combination of “Traders & Barbarians" with "Seafarers” Catan Event Cards + Seafarers (in general) - In scenarios without desert, what happens when the robber flees to the desert?

Answer

The robber is placed beside the game board, where he waits for his next mission – that is, until a “seven” is rolled or a Knight card is played.