Jinhae, former city, on Jinhae Bay, South Gyeongsang do (province), southern South Korea, now a district of Changwon city. Its picturesque natural harbor is protected by Geoje Island and Goseong Peninsula. During the Russo-Japanese War (1904–05) the Japanese navy used it as a base of operation, and it has since been developed into a naval port. In 2010 Jinhae, Changwon, and the neighboring city of Masan were redesignated as districts and joined administratively to create the unified city of Changwon. The headquarters of the South Korean navy and the South Korean Naval Academy are located in Jinhae. Because of its scenic beauty and its cherry blossoms, it has also developed as a tourist center. Pop. (2020) Changwon (including Masan and Jinhae), 1,029,389.