The defense ministers of Japan and South Korea have agreed to maintain close cooperation with the United States to deter North Korea’s nuclear threat and Pyongyang’s growing military ties with Russia, the South Korean defense ministry announced.
Japanese Minister of Defense Gen Nakatani and South Korean Minister of National Defense Ahn Gyu-Back, meeting in Seoul, South Korea, in September 2025, resolved to hold more talks, reaffirmed their commitment to denuclearization of the Korean Peninsula and pledged to pursue cooperation in advanced defense technologies.
The defense chiefs highlighted the importance of their participation in the annual trilateral Freedom Edge exercise, hosted by U.S. Indo-Pacific Command (USINDOPACOM). The September 2025 iteration, held against a backdrop of North Korea’s ongoing missile threats, featured upgraded aerial, naval and cyber capabilities, according to the South Korean defense ministry. The drills, which took place off South Korea’s Jeju Island, featured U.S. Marine Corps and U.S. Air Force assets in what USINDOPACOM said was the “most advanced demonstration of trilateral air and naval cooperation to date.”
The meeting of defense chiefs marked the first official trip to Seoul by a Japanese defense minister since 2015. Their session came after South Korean President Lee Jae Myung met with Japanese Prime Minister Shigeru Ishiba in August 2025 in Tokyo, where they agreed to form closer security and economic ties between their countries.
In Munich, Germany, in February 2025, Japanese Foreign Minister Iwaya Takeshi, South Korean Foreign Minister Cho Tae-yul and U.S. Secretary of State Marco Rubio released a joint statement reaffirming the trilateral partnership. They pledged robust security cooperation, regularly scheduled combined exercises and strengthened deterrence through U.S. alliances with both Seoul and Tokyo, underscoring opposition to any unilateral efforts to change the regional status quo by force in the Indo-Pacific.
The Allies’ trilateral cooperation comes as North Korea deepens military collaboration with Russia. In June 2024, Moscow and Pyongyang signed a defense pact pledging mutual aid, a move that analysts said raised the stakes for U.S. interests in East Asia and Europe. China’s recent military parade in Beijing, attended by North Korean leader Kim Jong Un, and increased Chinese patrols near disputed islands in the East China Sea, have further heightened regional tensions.