Kumamoto Castle is considered one of the three premier castles in Japan along with Himeji Castle and Matsumoto Castle. With large castle grounds and a variety of buildings, the castle offers visitors one of the most complete castle experiences in Japan.

Only a few structures have remained intact in the centuries since the castle's construction in 1607, so the castle keep and most other buildings are modern reconstructions.

The castle is currently under renovation after suffering serious damage in the 2016 earthquake. The inner grounds are currently closed to the public, but it is possible to look at the massive fortress from the outside. The interior of the castle's main keep is scheduled to reopen to the public in spring 2021, while the rest of the grounds are expected to require about 20 years to be fully repaired.

Suizenji Garden across the river is also well worth a visit. A spacious traditional-style garden built in the 17th century, the garden recreates in miniature the important road that linked Edo (Tokyo) and Kyoto, including a mini Mount Fuji.