Fehmarn Belt Tunnel: World’s Longest Immersed Tunnel Faces Delays

The Fehmarn Belt Tunnel, designed to connect Rødbyhavn in Denmark with Fehmarn in Germany, is one of Europe’s most ambitious infrastructure projects. Spanning 18 kilometers beneath the Baltic Sea, it will be the world’s longest immersed tunnel, carrying both road and rail traffic. Funded entirely by Denmark at a cost of €7.5 billion, the project is expected to reduce travel distances by 160 kilometers, significantly improving connectivity in northern Europe and supporting the EU’s transport decarbonisation goals.

Construction has reached a major milestone, with the first tunnel elements scheduled to be lowered into place in 2025. The design incorporates watertight seals and reinforced walls to enhance structural safety and resilience against external loads and potential water intrusion. Once completed, cars will pay a toll of €73, while rail charges are yet to be determined.

Recent Developments and Schedule Pressures

The tunnel’s construction schedule is currently under considerable pressure. Delays in delivering the immersion vessel which is the specialized pontoon needed to accurately lower tunnel elements, have postponed the immersion phase beyond original timelines. Though the first segments were expected to be immersed in 2025, these delays threaten the planned 2029 opening. A German rail-link tunnel, needed to connect with national rail infrastructure, may not be operational until around 2032, further delaying full rail service.

Learn more about one of the world’s most significant tunnel projects here.