Greek-born Postecoglou will replace French coach Erick Mombaerts, who said in early November he would be leaving the J-League club at the end of the season to return to Europe.
“I am excited to be moving to Japan and returning to club football,” said the 52-year-old Postecoglou in a statement, adding he was particularly looking forward to working with the club’s younger players.
Yokohama F-Marinos are part-owned by the City Football Group (CFG), who also own English Premier League club Manchester City, Major League Soccer’s New York City, Melbourne City in Australia and Uruguayan club Atletico Torque.
Club president Koichiro Furukawa said Postecoglou would encourage “an attractive and entertaining style of football which will suit our approach.”
Yokohama F-Marinos came fifth in the J-League last season, trailing champions Kawasaki by 13 points.
Australia have said they do not expect to appoint a coach for next year’s World Cup until February, amid a “high level of interest” in the job since Postecoglou stepped down.
Former United States boss and Germany legend Jurgen Klinsmann is reportedly keen on the job.
Australia have been drawn in a tough Group C at the World Cup, along with higher-ranked teams France, Denmark and Peru.
