The Seikan Tunnel spans 53.85 kilometers, with 23.3 kilometers running beneath the seabed.
The tunnel is located 100 meters below the seabed and 240 meters below sea level at its deepest point.
The museum uses the actual Tappi inclined railway track originally built to transport materials and personnel during construction.
The tunnel was designed to be earthquake-resistant, accounting for the region's high seismic activity.
Initial surveys for the tunnel began in 1946, though full-scale construction did not commence until 1971.
A commemorative plaque at the site lists the names of workers who died during construction, acknowledging the high human cost of the project.
The tunnel currently serves both the Hokkaido Shinkansen and local freight trains.
The museum occupies the facility where the 'Tappi-Kaitei' station was once located, formerly the world's deepest station.
Geological conditions were so complex that tunneling efforts frequently faced water ingress from the Tsugaru Strait.
The Seikan Tunnel Museum is located in Sotogahama, Aomori, directly above the Seikan Tunnel, which connects the islands of Honshu and Hokkaido. The museum is built at the site of the former Tappi inclined railway, which was used for construction logistics. Visitors can descend into the tunnel's actual service slant via a specialized cable car to reach a depth of 140 meters below sea level. Displays detail the engineering challenges of excavating beneath the Tsugaru Strait, including geological survey methods and heavy machinery usage. The facility serves as a memorial to the 34 workers who lost their lives during the 24-year construction period. Exhibits showcase the evolution of the Seikan Tunnel from a proposed bridge-tunnel hybrid project to its current status as the world's longest undersea railway tunnel. The site provides access to the actual working pit used by engineers during the tunnel's development.
The observation deck outside the museum offering views of the Tsugaru Strait and the Hokkaido coastline.
Bring a light jacket, as temperatures within the tunnel area are significantly cooler than the surface.
Wear comfortable, flat walking shoes for traversing the underground portions of the tour.
Allow ample time to read the technical signage, as it contains specific data regarding the tunnel's ventilation and safety systems.
Do not attempt to walk along the tunnel tracks outside the designated museum tour areas.
Closed during the winter months due to heavy snowfall; generally open from late April through early November.
Maintain a respectful tone in the memorial sections; adhere to all safety instructions provided by staff when descending into the tunnel.
