The 560-kilometre Western HVDC link will be used to supply renewable energy between England and Scotland.
DeepOcean's work will include pre-lay survey, pre-lay grapnel run, post-trench survey and trenching in depths of up to 165 metres.
Offshore work will commence in the second half of this year and continue through to 2016.
The Western HVDC link will run under the Irish Sea between Hunterston, western Scotland, and the Wirral in north-west England. The project's customers are National Grid Electricity Transmission and Scottish Power Transmission.
The connection will have a rating of 2.2GW and will be the first undersea interconnection using a direct current voltage level of 600kV.