Norway building world's longest underwater road tunnel

Norway is constructing the Rogfast tunnel, which is set to become the world’s longest and deepest underwater road tunnel. Located under the Boknafjord on the country’s west coast, the project spans 26.7 kilometers and reaches depths of up to 392 meters below sea level.

The tunnel will consist of two tubes, each with two lanes, and will include two traffic roundabouts located under the island of Kvitsøy. Once completed, the connection is expected to open in 2033, reducing travel time between Stavanger and Bergen by approximately 40 minutes.

Construction involves significant engineering challenges, including managing extreme water pressure and blasting through rock rather than using traditional tunnel boring machines. Recent reports from the Norwegian Public Roads Administration, Statens vegvesen, noted that safety protocols were tested during a vehicle fire at the site in February 2025, where workers successfully used a secondary escape route through a parallel tube.