The station, originally named , opened on 1 April 1984. During the 11 March
2011 Tōhoku earthquake and tsunami, part of the tracks and the station building at Shimanoshi were swept away, suspending services on a portion of the Sanriku Railway. However, the section of the line from Omoto to reopened on 29 March 2011, and the section from Omoto to reopened on 6 April 2014. From 27 December 2015, the station was renamed Iwaizumi-Omoto Station. The renaming was at the request of the town of
Iwaizumi, as no stations serving the town contain the name "Iwaizumi" following the closure of the JR East
Iwaizumi Line and
Iwaizumi Station in 2014. Minami-Rias Line, a portion of Yamada Line, and Kita-Rias Line constitute Rias Line on 23 March 2019. Accordingly, this station became an intermediate station of Rias Line. == Surrounding area ==