Seikan Tunnel - 24 Kilometers Under the Sea

Seikan Tunnel passes under Tsugaru Strait a distance of approximately 15 miles that separate Honshu from Hokkaido, the two largest of the Japanese islands.

by Bob Kerstetter

Just under 24 kilometers—approximately 15 miles—separate Honshu from Hokkaido, the two largest of the Japanese islands. The waters of Tsugaru Strait fill the space between, linking the Pacific Ocean with the Sea of Japan.

Seikan Tunnel passes under Tsugaru Strait. The strait connects the Pacific Ocean on the East and the Sea of Japan on the West. While local trains run through the tunnel 54km tunnel in 24 minutes, the rails can handle Shinkansen speeds.

Boats originally connected the islands. Airplanes followed. After hundreds of people died in a storm-generated ferry accident while crossing the strait in the mid-1950s, Japan started thinking about safer and more economical means of inter-island transportation. In 1988 the excavated tunnel under Tsugaru Strait added trains to the travel options.

Local train at Hakodate Station after running through Seikan Tunnel

The Seikan Tunnel runs 240 meters—almost 800 feet—below sea level. In exact measurements, the tunnel keeps you underground for 53.86 kilometers, 23.23 of these run 100 meters under the seabed. The ride feels quiet, smooth and fast. From end-to-end, the tunnel trip lasts approximately 24 minutes.

While the train is of local variety, the tunnel rails can handle Shinkansen speeds. The Japanese bullet trains hope to start running in fiscal 2015, renewing rail riding to Hokkaido as a time-effective alternative to air travel.

The back of each seat on the Hakucho and Limited Express Super Hakucho contains a cutaway draw of the Seikan Tunnel plus a train schedule. The travel time in the 53 kilometer tunnel is 24 minutes.