Prince William is leaving the armed forces after more than seven years of full-time military service.
William carried out his last shift on Tuesday and is now working towards expanding his core charitable interests, particularly the conservation of endangered species.
The Duke of Cambridge will continue to carry out royal engagements, but is not expected to increase his number of public duties.
The second in line to the throne is in a "transitional" year, sources have said, and is considering options for his "public service".
An announcement will be made about his decision within the next 12 months.
Air Chief Marshal Sir Andrew Pulford said Flight Lieutenant Wales had been an integral part of the RAF's search and rescue force as a Sea King pilot based in Anglesey.
"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," Sir Andrew said.
"He has earned the respect of all who have worked with him as a highly professional and competent pilot."
Kensington Palace said in a statement: "His Royal Highness The Duke of Cambridge is to leave operational service in the armed forces.
"He completes his tour with the Royal Air Force search and rescue force at RAF Valley, Anglesey, after more than seven-and-a-half years of full-time military service.
"He will continue to support the work of the Queen and the Royal Family through a programme of official engagements, both at home and overseas, with the Duchess of Cambridge.
"The Duke will work closely over the next 12 months with the Royal Foundation of the Duke and Duchess of Cambridge and Prince Harry.
"He will expand his work in the field of conservation, particularly in respect of endangered species.
