The visit saw US President Donald Trump play golf with Prime Minister Shinzo Abe. (File)

US President Donald Trump left Japan on Tuesday after a trip in which he became the first foreign leader to meet newly enthroned Emperor Naruhito.

Trump and his wife Melania boarded Air Force One at Tokyo's Haneda airport and were headed back to Washington, via a refuelling stop in Alaska.

They arrived Saturday on a visit that saw Trump play golf with Prime Minister Shinzo Abe, present a sumo wrestling trophy, and attend a state banquet with Naruhito. He wrapped up the tour with a visit to a US naval base.