The first 217-meter tunnel element slid into the Baltic on the 4th of May, and with it the Fehmarnbelt Fixed Link stopped being a casting yard and became a tunnel. When the full crossing opens, drivers and trains will pass under 18 kilometers of sea between Denmark and Germany in a tube resting on the seabed, the longest immersed tunnel ever built.

Project Scope

The link replaces a ferry route between Rødby on the Danish island of Lolland and Puttgarden on the German island of Fehmarn. It carries a four-lane motorway and a double-track electrified railway inside the same structure. The tunnel is assembled from 79 concrete elements, each 217 meters long, cast at a purpose-built factory on Lolland and floated out to a trench dredged across the strait. That dredging finished in 2024 and moved close to 15 million cubic meters of seabed. Fifteen elements have been cast so far, making up the first 2.7 kilometers of the route.

Why It Matters

The crossing cuts the Copenhagen-to-Hamburg rail trip to a fraction of today’s time and pulls freight off a congested ferry corridor and onto electrified track. For the contractors, it’s a reference job in immersed-tunnel construction at a scale no one has attempted, the same league of fixed-link engineering as the major rail tunnel programs moving forward elsewhere. The schedule has slipped: trouble with the immersion vessel means the 2029 opening is off the table, and the contractor is preparing a revised timeline now that elements are going in. The engineering is sound. The calendar is the part still being written. More detail sits with the project owner, Femern A/S.

Project Team & Details