Crusaders head coach Scott Robertson said Ioane and the Crusaders had reached a mutual decision that staying in Japan was best for the 32-year-old.
Ioane, who earned 35 caps for Australia from 2007 to 2013, played just three Super Rugby games for the Crusaders in 2017, scoring one try against the Western Force.
His season was hampered by hand and hamstring injuries and he was unable to win back his place with Seta Tamanivalu and George Bridge in good form on the wings.
