China is considering building a high-speed undersea rail tunnel under the Bohai Strait, in a project that would connect the cities of Dalian, in Liaoning Province, and Yantai, in Shandong Province. If completed, the new link would reduce travel time between the two cities from several hours to approximately 40 minutes.
The project is touted as one of the most ambitious underwater rail connections being discussed worldwide. The tunnel would be approximately 123–125 km long, with about 90 km of it underwater.
Currently, the connection between Dalian and Yantai involves either a sea crossing of the strait or much longer land routes that bypass the Bohai area. Through a direct connection, Chinese authorities aim to reduce travel time and strengthen economic integration between two major industrial regions.
High-Speed Trains Under the Bohai Sea
According to estimates circulating regarding the project, trains could travel at speeds of up to 250 km/h, although the actual operating speed through the tunnel could be lower, depending on the final technical solutions and safety regulations.
The tunnel would be part of a rail corridor capable of handling both passenger traffic and significant logistics flows. A direct connection between the cities of Dalian and Yantai would substantially shorten travel times between northeastern and eastern China, in an area with ports, industrial centers, and transport corridors that are crucial to the Chinese economy.
The project is also designed as an integrated link with China’s high-speed rail network, which would allow journeys to continue to other regions without major interruptions for passengers.
An investment of tens of billions of EUR
The cost of the project is estimated at 200–300 billion yuan, between 25 and 35 billion EUR. The scale of the investment is one of the main obstacles to the project’s progress.
In addition to costs, construction would pose considerable technical challenges. The Bohai Strait is an area with complex geological conditions, and the project would need to account for seismic risks, water infiltration, high pressures, and strict safety requirements for passenger evacuation in case of an emergency.
In the options discussed so far, the link could include parallel tunnels for train traffic and a central structure for maintenance, evacuation, and emergency response. Such solutions are frequently used in large-scale underwater projects to separate traffic flows and enhance operational safety.
From eight hours to 40 minutes
Currently, traveling between Dalian and Yantai can take six to eight hours, depending on the mode of transport chosen. The overland route requires a detour around the entire Bohai region, which significantly increases the distance traveled.
Via the tunnel, the rail link would reduce the route to just over 100 km and allow for a journey of approximately 40 minutes between the two cities. However, this estimate depends on the final route, the authorized speed, and integration with the rest of the Chinese rail network.
For freight transport, the project could reduce logistics costs and the time required to travel between two major economic zones. For passengers, it would transform a complicated journey into a fast connection between two urban centers on opposite sides of the strait.
A frequently cited target date for completion is 2035, but this should be treated as an estimate, not a firm timeline. Under conservative estimates, a project of this scale could take 10–15 years, depending on when final approval is granted and the financing model.
If completed, the tunnel under the Bohai Strait would surpass other global landmarks of underwater railway infrastructure in scale, including the Eurotunnel between France and the United Kingdom and the Seikan Tunnel in Japan. Until then, the project remains one of the most spectacular railway infrastructure plans discussed by China, but also one of the most technically and financially challenging.
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