Standing beside the Seto Inland Sea, Imabari Castle is one of the "Three Great Sea Castles of Japan” and renowned for its rare design that incorporates seawater-filled moats.

Built in the early 17th century by the master castle builder Todo Takatora, the castle once allowed boats to pass directly into its defenses, reflecting Imabari’s long history as a strategic maritime hub.

The reconstructed main keep now functions as a museum, offering insight into the castle’s role in regional history and the seafaring culture of the Inland Sea. Inside, visitors can explore exhibits featuring samurai armor, weapons, and historical documents connected to the Imabari domain.

At the top of the keep, an open observation deck provides sweeping views over the city, the surrounding moats, and the shimmering waters beyond—on clear days, you can even spot parts of the Shimanami Kaido.

The spacious grounds are ideal for a relaxed stroll, with impressive stone walls, corner turrets, and seasonal highlights such as cherry blossoms in spring. A museum shop near the keep sells Imabari Castle–themed souvenirs and commemorative castle stamps, making a fitting stop before continuing your journey.

Located close to Imabari Station and the start of the cycling route, a visit to Imabari Castle is a must if you are in Imabari before or after your time on the Shimanami Kaido.