German developer RWE Innogy said the project had been installed in just over a year after the first turbine was installed in May 2013.
Siemens' 3.6MW turbines are being used at the development located 13 kilometres from the North Wales coast.
A2Sea's Sea Worker and Sea Jack vessels were used to install the turbines. Work is still ongoing to bring the project online which RWE plans to be by the end of the year.
It will be the world's second largest operational offshore wind project when it is fully operational. Dong Energy's 630MW London Array project off the UK's east coast is currently the biggest.
Images supplied courtesy of Gwynt y Môr Offshore Wind Farm Limited.