Record #00447Transport archive
Japan's Seikan Tunnel runs beneath the Tsugaru Strait between Honshu and Hokkaido. Its 53.85 km total length includes 23.30 km beneath the seabed; the record concerns total length of a tunnel containing an undersea section, not the longest undersea segment.
Current Record
53.85km
Current record value
The Seikan Tunnel passes under the Tsugaru Strait. Construction involved high groundwater pressures, major inflows and difficult geology; the line opened in 1988.
The Hokkaido Shinkansen began using the tunnel in 2016. Dual-gauge infrastructure supports passenger and freight traffic.
The record compares total tunnel length of 53.85 km, not the 23.30 km undersea section; the Channel Tunnel has a longer undersea section.
The record conclusion has sufficient verification support.
Basis: direct confirmation by an authority
JRTT gives total length 53.85 km, of which 23.30 km is beneath the seabed, and confirms the 1988 opening. This record compares full lengths of railway tunnels having an undersea segment, not the longest submerged segment. The linear feature is parented to Japan without assigning an arbitrary point.
Current Entry identifies the current entry in this archive; it does not establish that the record is still held today.
The record value on this page is organized from the public sources above. Measurement methods may differ; JiLuDB follows the unified method described for each entry.
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