German Federal Audit Office Warns Hinterland Rail Link to Fehmarnbelt Tunnel Could Exceed €10.7 Billion

Deutsche Bahn confirmed in a written statement that it expects a significant cost increase, particularly due to inflation and the current situation in the construction industry. The company stated: "Richtig ist, dass wir von einer deutlichen Kostensteigerung, insbesondere aufgrund der Inflation und aktuellen Lage in der Baubranche, ausgehen müssen." It added that "Die neuen Kosten für die Schienenanbindung der festen Fehmarnbeltquerung befinden sich noch in der Ermittlung," meaning the precise final figure is still being determined.

Political reactions

Schleswig-Holstein's Economics Minister Claus Ruhe Madsen (CDU) sharply criticised the development, calling it "Eine unfassbare Summe. Es ist unglaublich, dass wir auf elf Milliarden gekommen sind." He added that a tripling of costs would be untenable, stating: "eine Verdreifachung der Kosten sei untragbar." At the same time, he stressed that the state treaty on the Fehmarnbelt crossing between Germany and Denmark, signed in 2008, must be honoured regardless of costs: "Der Staatsvertrag zur Fehmarnbelt-Querung zwischen Deutschland und Dänemark sei 2008 geschlossen worden - und ein Vertrag müsse unabhängig von den Kosten eingehalten werden."

Green Party budget politician Piechotta demanded that more economical alternatives be put on the table, calling for "Lösungen für eine wirtschaftlichere Schienenanbindung vorzulegen." The call for cheaper options reflects growing political pressure as the gap between original estimates and the audit office's projection widens.

Project timeline and local impact

The 88-kilometre rail link is a key component of the broader project. When complete, it is intended to enable travel from Hamburg to Copenhagen in about 2.5 hours starting in the early 2030s. The Fehmarnbelt Tunnel itself is an 18-kilometre railway and road tunnel designed to connect the German island of Fehmarn with the Danish island of Lolland, with completion originally targeted for 2029.

However, the overall project is already running late. The construction company Sund & Bælt has communicated that the Baltic Sea tunnel from Fehmarn to Denmark will not open before 2031, putting the project at least two years behind schedule. There is no precise timetable yet for when the first train will run on the new route, meaning the cost overruns and delays are feeding into broader uncertainty around the project's delivery date.

Local officials along the planned route have also voiced concerns about the impact of the project on their communities. Bad Schwartau mayor Katrin Engeln of the Green Party said 300 buildings in her municipality are affected by the construction of the hinterland connection. Fehmarn mayor Jörg Weber (SPD) was more resigned about the price tag, stating: "Es ist nicht verwunderlich angesichts der Baukostenentwicklung überhaupt im gesamten öffentlichen Bereich. Das ist aktuell überall so."

Background on the Fehmarnbelt project

Cost increases for the actual construction of the tunnel were already known before the latest revelations. The new audit office memo, which has existed since November, now adds a significantly higher bill for the German rail approach to the project's financial challenges. The news was broadcast on 4 June 2026 on the Deutschlandfunk program.

Taken together, the figures point to one of the most expensive transport infrastructure overruns in recent German planning. With a state treaty in place, a delayed tunnel, and a hinterland rail link that may now cost more than the tunnel itself, politicians and auditors are likely to continue clashing over how to keep the project viable without breaching fiscal or contractual boundaries.