On July 30, 2023, Aoimisima Sightseeing Marine Co., Ltd.'s passenger vessel 'Angel' departed Senzaki Port with 14 passengers. While navigating the Aoimisima sightseeing route, it ran aground on a shallow area near Shimamigamon and could not refloat itself, resulting in the vessel being inoperable. No injuries were reported. On August 31, 2023, the Kyushu Transport Bureau's Marine Operations Supervisor conducted an audit based on the Marine Transportation Law. On June 3, 2024, the bureau issued a warning to the company, including instructions that the voyage manager must promptly report any accidents and their details to the relevant transportation authorities and coast guard, and to do so sequentially as information becomes clear. The violation involved failure to adhere to these safety and reporting regulations.