The Hawks striker was the man of the moment on the final day of the National League South season.
He secured the title with a last-minute winner against Concord which meant Havant went up and not Dartford.
But Prior won’t be leading the line in Non-League’s top flight.
He has opted to join Bostik League Dorking for personal reasons. Lee Bradbury has since signed Darts forward Alfie Pavey.
The Surrey club paid an undisclosed fee to bring the former AFC Wimbledon striker to the club.
“We did offer Jason a new contract with these commitments in mind which Prior understandably turned down to focus on his family commitments,” read a Hawks statement.
“All at Havant and Waterlooville would like to thank Jason for his hard work during his time as a Hawks player, wish him well for the future and thank him for the memories.”