A Strategic Turning Point for Australia-South Korea Defense Cooperation

The Diplomat

a day ago

As of 2025, the Indo-Pacific region stands at the heart of a strategic turning point, where the reconfiguration of the international order is accelerating. Strategic rivalry between the United States and China has expanded beyond geopolitical disputes to technology, economics, military capabilities, and values. The protracted Russia-Ukraine War and the heightened tensions in the Taiwan Strait are also testing regional security networks.
In this context, recent changes in U.S. strategy demand careful scrutiny. With the slogan 'America First,' the Trump administration placed U.S. national interests above all else, pressing allies to boost defense budgets up to 5 percent of GDP. At the same time, Washington is reassessing its overseas military presence and wants to secure critical defense technologies at home, developments that directly affected allied deterrence frameworks. These changes make clear the necessity of new frameworks for allied cooperation to manage emerging security gaps in the Indo-Pacific.
South Korea is a representative middle power facing these complex challenges: it is exposed to China's strategic expansion and pressure while maintaining a traditional alliance with the United States. With the inauguration of the Lee Jae-myung administration, Seoul has declared 'pragmatic diplomacy' as its new foreign policy principle. This approach seeks to secure diplomatic space and strategic autonomy through flexible, multilayered engagement based on national interest. It also represents an attempt to redesign South Korea's national security architecture beyond a U.S.-dependent framework.
Australia could become one of the principal partners in advancing Seoul's pragmatic diplomacy. Canberra was engaged together with South Korea under the United Nations Command (UNC) during the Korean War and has, as a fellow U.S. ally, has participated with South Korea in multiple operations abroad, including Vietnam, Iraq, and Afghanistan. More recently, Vice Admiral Stuart Mayer of the Royal Australian Navy served as Deputy Commander of the UNC, reinforcing the institutional framework for potential support in a Korean Peninsula contingency. On the basis of this historical and institutional foundation, the scope for bilateral cooperation is expected to expand further.
In mid-August, the Ministry of National Defense of South Korea convened the second ROK-Australia Defense Conference in Canberra, marking a transition from historic camaraderie to a more strategic partnership. Participants emphasized that the complex regional environment compels middle powers to combine traditional alliances with innovative frameworks of cooperation, making closer coordination between Seoul and Canberra increasingly important.
'Australia is our partner for cooperation, which shares understanding in various fields based on a comprehensive strategic partnership,' a South Korean Defense Ministry official told Yonhap News after the conference.
Australia's Strategic Shift and Implications for South Korea
Australia has set a path toward a proactive and self-reliant posture, as outlined in the 2020 Defense Strategic Update, the 2023 Defense Strategic Review, and the 2024 National Defense Strategy (NDS). In particular, the 2024 NDS defines the Strategy of Denial as its core concept. With that goal, Australia has moved forward with major initiatives: acquiring nuclear-powered submarines, expanding long-range precision strike capabilities, reinforcing the defense industrial base, and reorganizing the armed force into a more integrated joint structure.
Australia's strategic shift offers distinct lessons for South Korea's own defense strategy. Geopolitically, South Korea is adjacent to continental powers, but its core national interests are generated through maritime domains. In this sense, Australia's approach – maritime-centered self-reliance, technology-driven force structure, and value-based diplomacy – offers highly practical insights and opportunities for strategic partnership with Seoul.
First, Seoul needs to move toward a dual-layered deterrence posture that extends beyond the current 'three-axis' system, which focuses exclusively on North Korea's nuclear threats. To achieve this, Seoul has to prepare for a wider range of Indo-Pacific contingencies by building strategic deterrence structures. A crucial element of this process will be enhancing interoperability and joint operational readiness with regional partners.
Second, Seoul should accelerate its transition toward maritime power. The 2022 Defense White Paper notes that the ROK Navy is strong in anti-submarine warfare and coastal operations, but limited in long-range precision strike, blue-water maneuverability, and strategic projection platforms. Australia is enhancing its distant deterrence through nuclear-powered submarines and long-range missile systems to secure independent capability as well as complement U.S. forces, and South Korea should similarly strengthen its strategic presence in the region.
Third, in addition to the South Korea-U.S. bilateral alliance framework, Seoul should construct a multilayered deterrence network through minilateral security groupings such as the Quad, AUKUS Pillar II, and the existing UNC framework – all of which include Australia as a member. The fact that both South Korea and Australia have experienced Chinese economic coercion provides a basis for developing an integrated strategic partnership encompassing political, economic, and security dimensions.
Core Areas for Future Cooperation
Australia-South Korea defense cooperation should move beyond symbolic ties toward practical capability integration and shared strategic goals in four key areas.
First, maritime security should be the most urgent priority. China's increasingly assertive activities in disputed waters have elevated this issue into a central challenge for the Indo-Pacific. South Korea and Australia have already accumulated experience through U.S.-led maritime exercises. Moreover, the ROK Navy's anti-submarine warfare capabilities and the Royal Australian Navy's strength in long-range patrols are highly complementary. Building on that foundation, they could conduct regular joint drills, connect them with Freedom of Navigation Operations (FONOPs), and expand information-sharing for maritime domain awareness.
Second, cooperation in cyber warfare is indispensable. Both countries face recurring cyber intrusions from China and North Korea, which makes coordinated responses essential. Australia responded to major breaches by enacting the Cyber Security Act and strengthening its Cyber Security Strategy. South Korea experiences similar attacks, particularly against its defense sector and critical infrastructure. Joint measures could involve a bilateral cyber threat response framework, bilateral cyber exercises, and exchanges of technical personnel.
Third, advanced technology cooperation presents opportunities for innovation in defense. AUKUS Pillar II provides channels for collaboration in artificial intelligence, hypersonics, quantum sensing, and autonomous systems. South Korean firms could participate in Australia's Ghost Bat and Ghost Shark programs by co-developing AI controllers, radar technologies, and satellite communications. Such collaboration would accelerate 'integrated innovation,' thereby ensuring the continuity of future cooperation.
Finally, institutionalizing defense cooperation is vital for long-term effectiveness. Formal agreements are needed to sustain and deepen bilateral defense cooperation. Upgrading existing dialogues into agreements – such as a Defense Cooperation Agreement (DCA) or Reciprocal Access Agreement (RAA) – would facilitate joint training, logistics, and deployments. A Defense Technology Cooperation Agreement (DTCA), a joint R&D fund, and expanded personnel exchanges would strengthen cooperation.
Conclusion
Australia could be an effective partner for advancing the Lee Jae-myung administration's pragmatic diplomacy. The two countries share valuable assets: institutional ties through the UNC, collaboration within AUKUS Pillar II, and complementary strengths in maritime, cyber, and advanced technologies. As the United States recalibrates its alliance system, South Korea must redesign layered deterrence and cooperation structures.
The goal is not to replace the U.S. alliance, but to reshape the regional security architecture, reinforce middle-power collaboration, and enhance South Korea's role as a strategic actor in the Indo-Pacific. Partnership with Australia can offer both near-term diplomatic agility and long-term strategic autonomy, but challenges remain. Effective cooperation will require balancing interoperability with technological sovereignty, reconciling strategic aims with domestic constraints, and sustaining stability while adapting to shifting environments.