Prince William will fly Sea King helicopters with the search and rescue unit at RAF Valley, about 352 kilometres west of London.Prince William will fly Sea King helicopters with the search and rescue unit at RAF Valley, about 352 kilometres west of London. (Reuters/Ministry of Defence)

After months of training, Prince William will graduate as a search and rescue helicopter pilot on Friday.

The prince's London office said William, who is second in line to the throne, will receive a certificate and his Royal Air Force squadron badge in a small ceremony on Friday.

Known in the air force as Flight Lieutenant William Wales, he will fly Sea King helicopters with the search and rescue unit at RAF Valley, which is about 352 kilometres west of London on the Irish Sea.

Britain's Ministry of Defence released footage of the prince on a training exercise to mark his graduation day.

In the video, William flies a yellow Sea King Search and Rescue helicopter with his instructor, along the coast of Anglesey, before performing a cliff winching exercise.

William said in a statement the course was challenging, but he "enjoyed it immensely. I absolutely love flying, so it will be an honour to serve operationally with the search and rescue force."

William's younger brother Harry is training to fly Apache attack helicopters.