Imabari Castle (今治城, Imabari-jō) is a Japanese flatland castle in Imabari, Ehime Prefecture, Japan. It was established by the Tokugawa shogunate in the Edo Period as the center of a feudal domain, the Imabari Domain.
Construction of the castle started in 1602 and was completed a year later in 1603. It was in active use for almost three centuries from 1602 to 1873. Its most distinguishable feature is a wide moat on all four sides that draws its water from the sea. Thus, the mote's water level rises and falls with the tide, and is a habitat for several seawater marine species. The moat’s width, about 60 meters across, served to be a strong fortification for the castle.
In 1871, the centralized government of Meiji Japan conducted mass reformations throughout Japan that established a new era. As the feudal system (the “han” system) was abolished and replaced by a new oligarchy, the Imabari Domain dissolved and Imabari Castle was incorporated as part of Ehime Prefecture. Parts of the castle were destroyed but later rebuilt in 1980 with materials and architectural styles that kept the castle as authentic as possible. Today, the castle is a historical monument that serves as a museum filled with stories and artifacts.