Moriyasu, Japan's longest-serving coach, was originally set to lead the team at the Asian Cup in Saudi Arabia in January before handing the reins to current Under-23 boss Go Oiwa.
But the Asian Football Confederation announced last week that the tournament would be pushed back to December 2027 due to "exceptional circumstances" in the region, following Houthi attacks on the host country.
That left Moriyasu in limbo, with Japan Football Association (JFA) chiefs last week declining to clarify when the coaching handover would take place.
They said on Friday that Japan's friendlies in Singapore against Brazil on Saturday and Paraguay on Tuesday would be Moriyasu's last in charge.
The 58-year-old took over after the 2018 World Cup.
He led Japan to shock wins over Germany and Spain on the way to a last-16 defeat on penalties to Croatia at the 2022 World Cup in Qatar.
He took them to the last 32 at this year's World Cup in North America, where they lost 2-1 to Brazil after a last-minute goal.
Moriyasu was set to lead the team in an Asian Cup warm-up friendly against a yet-to-be-named opponent in Osaka on December 30th.
The JFA said that the game had been cancelled.
"We had regarded this game as an important opportunity to strengthen the Japan team, and we had been making thorough preparations," JFA president Tsuneyasu Miyamoto said in a statement.
"But following the postponement of the Asian Cup and considering the national team's schedule, we have decided to cancel the game."