Croatia was used to film Outer Banks Season 5 scenes representing Portugal.
Production moved beyond the United States for parts of the final season. Croatian locations were used for scenes connected with Lisbon, Portugal, allowing the show to portray an overseas setting without filming every sequence in the actual Portuguese capital.
Using one place to represent another is common in television production. Filmmakers choose locations based on architecture, coastline, access, schedules, and available crews. Croatia’s historic cities and Adriatic scenery can provide visual details that work convincingly for European story locations.
The country is easy to confuse with Portugal because Portugal is the setting represented on screen. The filming country, however, was Croatia. Reports also identified Dubrovnik as one of the Croatian cities associated with the production, but the broader answer to the country question is Croatia.