Two 34km cables were installed by the Living Stone cable-lay vessel, as well as an 8km interlink cable, the company said.
DEME said the complex project included the crossing of the Maasmond shipping route, characterised by heavy traffic to and from the Port of Rotterdam.
The work was carried out on behalf of Van Oord, the company added.
The cables will link the Hollandse Kust Zuid Beta offshore platform to the Dutch grid.
