In Japan, "Fossil Day" is celebrated annually on October 15th. This date was chosen by the Palaeontological Society of Japan in response to the establishment of the International Fossil Day by the International Palaeontological Association.

The specific date of October 15th holds significance in Japan as it marks the day when the ammonite species Nipponites mirabilis was first described by Professor Hisakatsu Yabe from Tohoku University in 1904. This fossil species is also the symbol of the Palaeontological Society of Japan. The aim of celebrating Fossil Day is to raise public awareness about fossils and palaeontology, and to spark interest in the history of life and Earth. During Fossil Day, various activities are organized across Japan, including exhibitions, educational workshops, and fossil excavation experiences.