Known as Mako Komuro after giving up her royal title to marry college sweetheart Kei Komuro last month, the former royal and her husband, both 30, walked past waiting journalists at Tokyo's Haneda International Airport.
Well-wishers waved from the terminal as the plane left the gate.
Their marriage captivated Japan and ignited a public dialog about gender roles and media coverage of the royal family. Mako was diagnosed with post-traumatic stress disorder this year after their engagement was plagued by a money scandal, intense media scrutiny and the couple's three-year separation.
After the wedding, Mako, daughter of Crown Prince Akishino and Crown Princess Kiko, received her first passport so she could accompany Kei to New York, where he works at a law firm.