Utsuro-bune (虚舟, hollow boat), also Utsuro-fune and Urobune, was an unknown object that allegedly washed ashore in 1803 in Hitachi province on the eastern coast of Japan. Utsuro means "hollow" and -bune (from fune) means "boat". Accounts of the incident appear in four texts: Oushuku Zakki (1815), Toen Shōsetsu (1825), Hyōryū Kishū (1835) and Ume-no-chiri (1844).

According to the legend, a young woman aged between 18 and 20 arrived aboard the "hollow boat" on February 22, 1803. Fishermen brought her inland, but she was unable to communicate in Japanese. The fishermen returned her and her vessel to the sea, and it drifted away.