Emperor Akihito and Empress Michiko left for the Czech Republic on Saturday morning, the first leg of a two-week European tour that will also take them to Poland, Austria and Hungary.
The visit is the couple's first overseas trip since they visited the Netherlands, Sweden, Switzerland and Finland in May 2000 and their 10th since the Emperor ascended the throne in 1989.
Crown Prince Naruhito, Princess Masako and Prime Minister Junichiro Koizumi were among those who saw them off at Tokyo's Haneda airport.
The Imperial couple arrived in the Czech Republic on Saturday afternoon, they will visit Poland on Tuesday and Austria on Saturday before arriving in Hungary on July 16.
The Poland and Hungary legs of the tour are official state visits. They will return home on July 20, according to the agency.
Former Foreign Minister Masahiko Komura is serving as the chief attendant.