Iyomishima (伊予三島市 Iyomishima-shi) was a city located in Ehime, Japan.
On April 1, 2004 Iyomishima was merged with the town of Doi, the village of Shingū, both from Uma District, and the old city of Kawanoe, to form the new city of Shikokuchūō.
As of 2003, the city had an estimated population of 37,010 and the density of 199.94 persons per km². The total area was 185.11 km².
The city was founded on November 1, 1954.