World’s Deepest Underwater Tunnel To Have Cars Drive 16 Miles Under The Sea

Norway is embarking on one of the most ambitious infrastructure projects in the world with the construction of the Rogfast tunnel, set to become the longest and deepest road tunnel under the sea. Stretching 26.7 kilometers (about 16.5 miles) and plunging to depths of nearly 392 meters (almost 1,300 feet) below sea level, Rogfast is scheduled for completion and full operation by 2033.

Once finished, the tunnel will drastically cut travel time between Stavanger and Bergen, two of Norway’s largest cities, and form a vital piece of the broader E39 highway development. Currently, the E39 is a 21-hour journey dotted with ferry crossings. Rogfast aims to reduce that time by nearly half, delivering smoother, uninterrupted transport along the country’s rugged western coast.

The Rogfast tunnel is part of a broader national plan to eliminate ferry crossings along the E39 coastal highway, which runs from Kristiansand in southern Norway to Trondheim in the north. This particular segment will link the municipalities of Randaberg and Bokn directly by road, eliminating the need for ferry transport and improving regional logistics.

Construction on Rogfast began in 2018 and is divided into three main tunneling sections. Swiss-Norwegian joint contractors Implenia/Stangeland Maskin are managing two of these sections, while Swedish construction firm Skanska is handling the third. All three are employing drill-and-blast methods to bore through the seabed, with approximately 8 million cubic meters (over 280 million cubic feet) of rock being excavated. The tunnel will consist of twin tubes, each about 15 meters apart, carrying two lanes of traffic.

At the heart of the tunnel will be a submerged interchange located near the island of Kvitsøy. This central junction and the adjoining ventilation shafts extending more than 200 meters above the tunnels—represent some of the most technically complex aspects of the project. Driving the entire length of Rogfast at the projected speed of 50 km/h (just over 30 mph) is expected to take around 35 minutes.

Rogfast is a strategic investment in Norway’s economic core. The surrounding regions are vital to the country’s oil and seafood sectors, and the tunnel is expected to carry an average of 6,000 vehicles per day once operational. Officials believe this will benefit not only industry but also workers who commute between Bergen and Stavanger. “We hope that this project will reduce travel time for workers as well,” said Oddvar Kaarmo, Rogfast’s project manager.

The total cost of the tunnel is estimated between £1.45 billion and £1.74 billion (around $2 billion to $2.4 billion). The Norwegian government will cover approximately 40% of that amount, with the remaining funds raised through tolls, which are expected to cost about £30 (roughly $38) per trip.