South Korea has acknowledged discussions with Japan over a proposed bilateral military logistics support agreement, even as Seoul maintained clear reservations about moving forward, Defence Minister Ahn Gyu-back confirmed on Sunday, 1 June 2025. The disclosure, made on the sidelines of the Shangri-La Dialogue in Singapore, marks the first time a Seoul official has publicly confirmed that an Acquisition and Cross-Servicing Agreement (ACSA) featured on the bilateral defence agenda.

What Was Discussed

Ahn told reporters that the ACSA — a framework typically used to facilitate the sharing of logistics, supplies and services such as food, fuel and transportation between allied militaries during contingencies — was raised during his bilateral meeting with Japanese Defence Minister Shinjiro Koizumi on Saturday. He declined to elaborate further on the specifics of those talks.

A Defence Ministry official in Seoul was more direct: 'An ACSA is premature at this stage, and we are not reviewing the matter,' the official noted, signalling that any formal agreement remains distant.

Why Seoul Remains Cautious

Tokyo has been pushing for a bilateral ACSA with Seoul as part of a broader effort to strengthen military coordination — both bilaterally and in a trilateral framework with the United States — aimed at countering North Korean threats and China's growing assertiveness in the region.

Seoul's hesitation, however, is rooted in multiple layers of sensitivity. Chief among them is concern that such a pact could open the door for Japan's Self-Defence Forces to conduct operations on the Korean Peninsula. South Korea also weighs its ties with Beijing carefully, and the deep historical wounds from Japan's 1910–1945 colonial rule of Korea continue to cast a long shadow over defence cooperation.

'As this is a matter that requires understanding and persuasion from the people of both countries, we still believe that we should remain cautious,' Ahn said.

OPCON Transfer: A Separate Friction Point

Separately, Ahn addressed remarks made by US Defence Secretary Pete Hegseth at the Shangri-La Dialogue plenary on Saturday, in which Hegseth called for a 'balanced' approach to the transfer of wartime operational control (OPCON) — the command authority over South Korean and US forces that has been held by the US-led combined command since the Korean War.

Seoul is seeking to reclaim OPCON before the Lee Jae Myung government's five-year term concludes in 2030. However, US Forces Korea Commander General Xavier Brunson has indicated the first quarter of 2029 as a potential transition window, and the two allies have yet to announce a formal target year.

Hegseth's call to 'honour' the roles the US military has played for decades on the peninsula drew attention amid signs of diverging timelines between Washington and Seoul. Ahn sought to soften the contrast: 'My understanding is that (the Secretary) meant to call for working together to align our efforts and energy (to move it forward),' he said.

Significance of the Disclosure

This is the first official acknowledgement from Seoul that an ACSA was formally on the table in defence-level talks with Tokyo — a notable shift in transparency, even if the substantive position remains unchanged. Analysts note that the trilateral US-South Korea-Japan security architecture has deepened considerably since 2023, making the absence of a bilateral ACSA between Seoul and Tokyo an increasingly conspicuous gap.

How Seoul navigates its historical sensitivities with Tokyo while keeping pace with Washington's expectations for tighter trilateral defence integration will remain a defining challenge for the Lee administration in the months ahead.