William, who has served as a search-and-rescue helicopter pilot in Wales since 2010, completed his final shift earlier this week.
He will continue to support the work of the Queen and the Royal family through a number of official engagements, both at home and abroad along with his wife Catherine, the Duchess of Cambridge.
"The Duke is currently considering a number of options for public service," a release said.
William, who is second in line to the British throne, will focus on his work on endangered species and is "considering a number of options for public service."
His wife Kate gave birth to the couple's first child, Prince George, in July.
William, Kate and their newborn son are expected to move into their official residence at Kensington Palace in London in the coming weeks.
The couple had been living in a rented home on the quiet island of Anglesey in north Wales, where they were able to enjoy a degree of privacy among residents and fellow military personnel.
Kensington Palace said William had participated in 156 search-and-rescue operations, helping to rescue 149 people. He has completed more than 1,300 flying hours.
William's younger brother, Prince Harry, remains active in the military and has served in Afghanistan as an Apache helicopter pilot.