During the Russo-Japanese War, "Akagi" assisted in the Siege of Port Arthur. On 2 May 1904, she assisted in the attempted blockade of the channel leading into the port. She was later sent to the western coast of Kwantung Peninsula to provide fire support during the Battle of Nanshan. While on patrol outside Port Arthur on 18 May 1904 she collided with the gunboat , which subsequently sank. "Akagi" later participated in the Invasion of Sakhalin.