The city of Ōfunato was originally part of the ancient Mutsu Province. It has been settled since the Jōmon period. The modern village of Ōfunato was made within Kesen District, Iwate on April 1, 1889. In 1896, the Meiji-Sanriku earthquake caused a 25-meter tsunami that killed 27,000 people in Sanriku. Ōfunato was promoted officially promoted to town status on April 1, 1932. In 1933, a 8.4 magnitude earthquake stuck the town and caused a 28-meter tsunami that killed 1522 people. On April 1, 1952, the town of Sakari, and villages of Akasaki, Takkon, Massaki, Ikawa and Hikoroichi all merged with Ōfunato to form the city. On November 15, 2001, the town of Sanriku (from Kesen District) also merged into Ōfunato.