In January 1868 Kaiyō Maru was engaged in the naval battle of Awa off Awaji Island, where she, Banryū Maru and Hazuru Maru battled against the Satsuma Navy's Kasuga Maru, Hōō Maru, and Heiun Maru.
During the battle, Hōō Maru was sunk off the coast of Awa.

In late January 1868, Kaiyō Maru, Kanrin Maru, Hōō Maru,  and five other modern ships fled to Hokkaido, under Admiral Enomoto Takeaki.
They carried a handful of French military advisors, and their leader Jules Brunet.
While in Hokkaido, they became a part of the navy of the short-lived Ezo Republic, founded by Enomoto Takeaki.
Kaiyō Maru became the flagship of the navy of the Ezo Republic, but she soon was wrecked off Esashi, Hokkaido, Japan, during a storm on 15 November 1868.
The steamship Shinsoku made a rescue attempt, but it too sank.
In January 1868 Kaiyō Maru was engaged in the naval battle of Awa off Awaji Island, where she, Banryū Maru and Hazuru Maru battled against the Satsuma Navy's Kasuga Maru, Hōō Maru, and Heiun Maru. During the battle, Hōō Maru was sunk off the coast of Awa.
In late January 1868, Kaiyō Maru, Kanrin Maru, Hōō Maru,  and five other modern ships fled to Hokkaido, under Admiral Enomoto Takeaki. They carried a handful of French military advisors, and their leader Jules Brunet. While in Hokkaido, they became a part of the navy of the short-lived Ezo Republic, founded by Enomoto Takeaki. Kaiyō Maru became the flagship of the navy of the Ezo Republic, but she soon was wrecked off Esashi, Hokkaido, Japan, during a storm on 15 November 1868. The steamship Shinsoku made a rescue attempt, but it too sank.
Japanese frigate Kaiyō Maru