Sif said the 77 foundations are scheduled to be made between July and December 2018, subject to the project's final investment decision.
The Dutch fabricator said the turbines will be installed directly onto the monopile foundations, without transition pieces.
The site will use MHI Vestas turbines, following a preferred supplier agreement between Blauwwind and the turbine manufacturing joint venture in March 2017.
The order was placed by the project's engineering, procurement and construction contractor Van Oord — which is also a member of the ownership consortium.
Borssele III & IV were awarded to the consortium with a strike price of €54.50/MWh in December 2016.
As well as Van Oord, Blauwwind members include oil and gas giant Shell, Dutch developer Eneco, Mitsubishi's European subsidiary Diamond Generating Europe and Swiss investment manager Partners Group.