Nord Stream 2 has started the offshore preparatory works for the pipelaying in the Bay of Greifswald, in the Baltic Sea off the German coast.
Five dredgers are working on the trench for the two pipeline strings.
The pipeline is needed to cover part of Europe's future natural gas supply gap.
The works in German territorial waters and at the landfall facilities were approved by the Stralsund Mining Authority on January 31.
Offshore preparatory works have also started in Finland, which has also granted all the necessary permits for construction and operation.
The other three countries along the route – Russia, Sweden and Denmark – are proceeding, with permits expected to be issued in coming months.
Scheduled construction works will be implemented in 2018.