The programme required almost 2,800 metres of seabed cone penetration testing and 5,000 metres of boreholes over the 407 kilometre square project area. Surveying was carried out by subsea firm Fugro.
Testing was carried out at each future turbine and substation position. Dong said it took approximately four months to complete.
Dong's site investigation project management team leader Soren Egede Johannesen said it was the biggest survey the company had ever taken on, and one of the largest ever in the offshore industry.
Fugro used its Greatship Manisha and Bucentaur vessels to carry out the survey.
Dong acquired rights to the project from the Smart Wind consortium in February. Hornsea 1 is part of the 4GW Hornsea Zone.