LONDON - There will be no more perilous military helicopter missions for Prince William in the rugged mountainous terrain of northern Wales.

With the military's announcement Thursday that he has completed the operational phase of his career, William looks free to spend more time with his wife, Kate, and their 2-month-old son, Prince George, while he takes on more royal engagements and charity roles.

The move marks the end of an exciting phase in the prince's life - he became adept at piloting a Sea King helicopter in foul weather, helping mountaineers in distress and rescuing mariners in the frigid waters of the Irish Sea. His active military career, a traditional rite of passage for senior royals, lasted more than seven years, first in the Army and then in the Royal Air Force.

Air Chief Marshal Andrew Pulford said William had been an important part of the Royal Air Force's search and rescue force for the past three years.

"Throughout his tour his airmanship, often in the most demanding of conditions, has contributed directly to saving lives in the mountains of North Wales and from the ravages of the Irish Sea," Pulford said. "He has earned the respect of all who have worked with him as a highly professional and competent pilot."

William, 31, started as an officer cadet at Sandhurst military academy in 2006. He began search and rescue helicopter training three years later and has the RAF rank of Flight Lieutenant, similar to a captain in the US Air Force.

The military said he had participated in 156 search and rescue operations, helping to rescue 149 people. He has completed more than 1,300 flying hours.

The palace said William would "expand his work in the field of conservation, particularly in respect of endangered species" and would work on charities that help children and veterans.

As part of his growing emphasis on wildlife protection, William on Thursday teamed up with sports stars David Beckham and Yao Ming to record public service announcements designed to reduce demand for rhino horn and ivory.

William spent his air force time stationed on the quiet rural island of Anglesey.

He was able to blend in with residents and fellow military personnel, enjoying a degree of privacy. Kate - known formally as the Duchess of Cambridge - was often seen shopping at local grocery stores, and the royal couple were able to go to pubs and restaurants without attracting unwanted attention.

Now that William's active military career is finished, the family will move into a refurbished apartment at Kensington Palace in London. They had been living in a rented home in Anglesey.

William's younger brother, Prince Harry, remains active in the military, and has served in Afghanistan as an Apache helicopter pilot with the army rank of captain.