DeepOcean will carry out all marine works for the cable, including installation and protection.
Work will begin in 2016 and is due for completion in 2018, DeepOcean said. It will link the countries between Ramsgate, in southeast England, to Herdersbrug, northwest Belgium. Commissioning of the link is expected in 2019.
J-Power Systems, a subsidiary of Japanese firm Sumitomo Electric Industries, awarded the contract in June.
Also in June, Siemens won the deal to supply high-voltage direct-current converter stations for the 141km link.
The 1GW connection project is developed by a joint venture between transmission operators the UK's National Grid and Belgium's Elia Group. It was given the go-ahead in February 2015.
The subsea power link will allow wind and other forms of renewable power to be exchanged between the two countries.