Japan, South Korea Agree to Strengthen Defense Cooperation

Japan’s and South Korea’s defense ministers agreed on Jan. 30 to strengthen their defense cooperation and work together to maintain peace and stability in the region.

Japanese Defense Minister Koizumi Shinjiro and South Korean Defense Minister Ahn Kyu-back met in Yokosuka, Japan, where they confirmed both countries would develop their cooperation in future-oriented technologies and fields, including artificial intelligence, unmanned systems, and space.

The meeting in Japan followed on from Koizumi’s visit to South Korea in September 2025.

According to a joint statement, Koizumi and Ahn agreed to hold visits and other exchanges and to conduct joint search-and-rescue operations.

The statement noted that the two parties had already conducted some exchanges, including between Japan’s Ground Self-Defense Force Officer Candidate School and three South Korean military academies this month, as well as South Korea’s Air Force Black Eagles’ first-ever flight visit to Naha Air Base in Okinawa.

“The two ministers agreed to cooperate to maintain peace and stability in the region amid an increasingly severe security environment, reaffirmed their commitment to the complete denuclearization of the Korean Peninsula and the establishment of lasting peace, and agreed to continue Japan-ROK and Japan-US-ROK cooperation,” the joint statement said.

ROK refers to the Republic of Korea, South Korea’s official name.

On Jan. 13, Japanese Prime Minister Sanae Takaichi and South Korean President Lee Jae Myung held a two-day summit in Japan, agreeing to deepen cooperation amid regional security and diplomatic challenges.

Both nations also have strong ties with the United States. Lee and Takaichi reaffirmed the strategic importance of their cooperation with Washington.

“The importance of Japan–South Korea relations, as well as cooperation among Japan, South Korea, and the United States, continues to grow,” Takaichi said in a joint statement alongside Lee.

The leaders’ summit earlier this month and Friday’s pledge to deepen defense cooperation between the two nations demonstrate that the two nations are drawing closer together, militarily and politically, following a history of conflict between Southeast Asian neighbors.

In the past century, relations between the two nations have become strained, in particular due to Japan’s colonial occupation of the Korean peninsula between 1910 and 1945. In recent years, Tokyo and Seoul have sought to address historical grievances and mend their relationship.

Other Defense Partnerships

Japan and South Korea have been working to deepen defense cooperation with partners in the region and with the United States.

On Jan. 26, Gyu-back met with U.S. Undersecretary of War Elbridge Colby to discuss the alliance, including the security situation on the Korean Peninsula and strengthening national defense capabilities. The United States also agreed to closely cooperate on South Korea’s pursuit of nuclear-powered submarines—vital in preparing to counter any potential security threat in the region.

Takaichi recently reaffirmed Japan’s commitment to its relationship with the United States, saying on Jan. 26 that if China and the United States were to engage in conflict over Taiwan, Japan would work alongside the United States to protect Japanese and American citizens in Taiwan.

“I want to make it absolutely clear that this is not about Japan going out and taking military action if China and the United States come into conflict [over Taiwan],” Takaichi said during a program featuring major party leaders on TV Asahi.

“If something terrible were to happen there, we would have to go and rescue the Japanese and Americans in Taiwan. In such a situation, joint action may be necessary.”

Regional tensions have heightened after Takaichi said in November 2025 that an attack on Taiwan would be deemed an existential threat to her country, prompting retaliatory action from China, including Beijing’s banning of dual-use exports to Japan.

Beijing considers the democratic, self-governing nation of Taiwan its own territory, and the communist regime has not ruled out taking control of the island by force. Taipei rejects Beijing’s territorial claim.