The Femern construction keeps postponing the schedule

A series of German authority documents now provide insight into what Femern A/S has officially reported as the schedule for the submersion of the 89 tunnel elements that will ultimately create a fixed link between Denmark and Germany. 

The plans show that the contractor in the spring and summer of 2025 has repeatedly changed the date for when the work at sea should begin. Initially, September was set, but over the summer the start date was postponed again and again.

The documents, which FemernBusiness has obtained access to, were submitted by Femern A/S to the German authorities. Primarily to the road and traffic authority in Schleswig-Holstein, but also to the federal authorities.

The start date is crucial because the submersion is the very core of the construction of the Fehmarn Belt link. The project is one of Europe's largest construction works and will connect Lolland with the German island of Fehmarn via an 18-kilometre-long immersed tunnel. The tunnel consists of 89 concrete elements, each over 200 metres long and weighing more than 70,000 tonnes. Lowering the elements to the bottom of the belt and connecting them is the most complex and weather-sensitive work in the entire project. The start date and pace of the submersion are the things that currently indicate a delay.

More obstacles

But several things stand in the way of the submersion beginning. The tunnel trench, where the elements are to be placed, has not been approved by the contractor Femern Link Contractors. Additionally, the vessel that is to tow and submerge the tunnel elements is awaiting approval from the Danish Maritime Authority.

The schedule submitted on 5 May showed that the work was to begin in mid-September. That plan was repeated a month later in the version from 2 June. But in the subsequent update, dated 30 June, the start time was moved to mid-October. And in the latest version, dated 4 August, the commencement was postponed once again, this time to the end of October. 

Three years of submersion

In the submitted schedules, only a start time is stated. The end date is not specified. But according to the contracts, the submersion of the 89 tunnel elements takes at least three years, followed by an additional two years of installation and testing before the tunnel can be opened. The period is already challenged by several factors: strict noise limits where even minor exceedances can trigger a halt in work, and the weather in the Fehmarn Belt, where wind, waves, and currents can prevent submersion operations from being carried out as planned. 

The official schedules are in sharp contrast to the internal documents submitted by the contractor Femern Link Contractors to the client. A status report from July 2025 reveals that the tunnel trench is not approved, and the first immersion can take place at the earliest on 9 May 2026.

From milestone to problem: Why the tunnel trench is not approved

Status report shows that the 18-kilometre-long tunnel trench does not meet the requirements. We review the six biggest problems.