2023 saw the beginning of a marked improvement in Japan-South Korea relations, which for decades had been marred by historical animosities. This upward trajectory continued throughout 2024. Coinciding with the early stages of the rapprochement, both nations’ relationships with the People’s Republic of China (China) deteriorated on several fronts. Soon after, the two nations moved closer to the US, reinvigorating a trilateral partnership focused on closer security and economic cooperation.

This report assesses the causes and outcomes of the shift, arguing that the growing trilateral partnership with the US makes Japan and South Korea key partners for advancing Australia’s economic interests and perspectives on regional security.

It also argues that the Tokyo-Seoul rapprochement could be a precursor to new forms of interplay between industry, security and foreign policy – for which Canberra should develop pre-emptive diplomatic and industry policy measures.

Key findings

• The recent rapprochement between Japan and South Korea was driven not only by shared security concerns, but also by challenges posed by the China's technological rise.
• This followed the China shifting from a largely complementary trade partner to both nations, to a competitive threat that overshadowed the two nations’ own longstanding trade rivalries.
• Japan-South Korea bilateral meetings have  focused on cooperation to diversify supply chains and strengthen cutting-edge technology industries.
• The alignment of this agenda with Washington’s tech war with Beijing helped strengthen the Japan-South Korea-US trilateral partnership, through which Japan and South Korea have gained access to US industry subsidies and supply chains.
• Japan and South Korea’s tech industry cooperation could provide new opportunities for exports, investment and technology transfer for Australia’s critical minerals sector.