Indonesia Security Report — September 25, 2026

Security analysis based on open-source intelligence and web research. Period: September 18 — September 25, 2026.

Executive Summary

Indonesia experienced a dynamic security landscape between September 18 and September 25, 2026, marked by significant international engagement and domestic security concerns. The nation hosted "Trident Resolve 2026," a major ASEAN-led disaster response exercise involving 19 countries, underscoring its commitment to regional stability and humanitarian cooperation. Diplomatic efforts intensified at the UN General Assembly, where Indonesia championed global resilience, UN reform, and the Palestinian cause, while also pursuing a non-permanent seat on the UN Security Council. Domestically, cybersecurity emerged as a critical vulnerability, with reported losses of US$6.2 billion from cyberattacks this year and ongoing efforts to bolster national cyber resilience. The period also saw continued challenges in West Papua regarding impunity for security force violence and the management of potential mass demonstrations.

Key Security Developments

• Military Activities and Exercises - Exercise Trident Resolve 2026 Concludes
  Indonesia hosted "Exercise Trident Resolve 2026" in Banten, West Java, from September 20 to 26, bringing together approximately 2,200 military personnel and civilian officials from 19 countries, including all 11 ASEAN nations and eight partners (Australia, China, India, Japan, New Zealand, Russia, South Korea, and the United States). This exercise, the largest under the ASEAN Defence Ministers' Meeting-Plus (ADMM-Plus) framework in a decade, focused on disaster response scenarios, including earthquakes, volcanic eruptions, and tsunamis, and integrated cybersecurity, humanitarian assistance and disaster relief (HADR), and military medicine. The exercise highlighted Indonesia's role in fostering regional cooperation and strengthening collective capabilities for complex emergencies.

• Defense Policy and Strategic Shifts - Enhanced US-Indonesia Defense Partnership
  The 2026 iteration of "Super Garuda Shield," which concluded on September 11, held special significance as Indonesia and the United States elevated their military relationship to a Major Defense Cooperation Partnership in April. This pact emphasizes military modernization, troop training programs, development of advanced defense measures, next-generation technologies, and cooperation on maintenance, repair, and overhaul to ensure readiness. The exercise, involving approximately 5,000 personnel from 15 participating and six observer nations, showcased enhanced interoperability across land, air, maritime, and cyber domains.

• Diplomatic Relations - Active Engagement at UN General Assembly
  Foreign Minister Sugiono led Indonesia's delegation at the 81st United Nations General Assembly in New York, which opened on September 22. Indonesia used this platform to advocate for greater international efforts to resolve conflicts, advance UN reform, and strengthen the voice of the Global South, particularly regarding the Palestinian cause. Sugiono held bilateral meetings with counterparts from the UK, Netherlands, and Germany to strengthen ties and discussed UN peacekeeping missions, with Indonesia and the Netherlands set to co-host the 2027 UN Peacekeeping Ministerial in Jakarta.

• Diplomatic Relations - Walkout During Netanyahu's UN Speech
  On September 24, Indonesian diplomats joined dozens of international envoys in walking out of the UN General Assembly as Israeli Prime Minister Benjamin Netanyahu prepared to deliver his national statement. This coordinated demonstration, following a memorandum from the Palestinian delegation, underscored Indonesia's strong opposition to Israel's ongoing military campaigns in Gaza and the West Bank and its unwavering support for Palestine.

• Security Incidents and Threats - "Black September" Protest Rumors
  Rumors of a "Black September" mass demonstration, identified with a large-scale protest potentially taking place on September 24, spread widely on social media. The Deputy Chief of the Indonesian National Police, Commissioner General Dedi Prasetyo, warned officers to prepare, though political and intelligence analyst Boni Hargens suggested the threat, while exploiting historical moments, was manageable. The Indonesian National Armed Forces (TNI), National Police (Polri), and State Intelligence Agency (BIN) were noted to have mitigation measures in place.

• Defense Acquisitions and Arms Deals - Italian Aircraft Carrier Visit
  The ITS Giuseppe Garibaldi-551 aircraft carrier from Italy docked at Pier 107 of Tanjung Priok Port in Jakarta on September 18. This visit is part of ongoing defense cooperation between Indonesia and Italy, aiming to strengthen Indonesia's maritime capabilities and support military operations other than war, particularly in disaster response and humanitarian assistance.

• Cybersecurity - Significant Financial Losses and Summit
  Bank Indonesia Governor Destry Damayanti reported on September 24 that cyberattacks have caused an estimated US$6.2 billion in damage in Indonesia this year alone, highlighting deepening cybersecurity risks from automation and AI. The 9th edition of IndoSec, Indonesia's largest cybersecurity summit, was held from September 15-16 in Jakarta, convening over 2,000 professionals to address national cyber resilience, zero trust architecture, cloud security, AI integration, and cyber warfare preparedness.

• Maritime and Border Security - Java Sea Ferry Disaster
  Search and rescue operations continued until at least September 18 for the passenger ship Virgo Transport 8, which capsized and sank in the Java Sea on September 13. The vessel, carrying 243 people from Surabaya to Banjarmasin, capsized in bad weather, resulting in 9 confirmed deaths and 126 passengers still unaccounted for by September 18. Authorities faced challenges due to strong currents and large waves, with plans to right the sunken ship to facilitate further recovery efforts.

• Counter-terrorism - Australia-Indonesia Collaboration
  Indonesia and Australia reaffirmed their commitment to combating terrorism through stronger early detection and mitigation measures during the 11th Indonesia-Australia Bilateral Consultation on Counter-Terrorism, held on September 17. The meeting, attended by Indonesia's National Counter-Terrorism Agency (BNPT) Head Eddy Hartono and Australian Ambassador for Counter-Terrorism Gemma Huggins, focused on refining bilateral programs and addressing complex threats like online radicalization and the use of emerging technologies by terrorists.

• Intelligence Activities - West Papua Impunity Concerns
  A report on September 17 highlighted a recurring pattern of impunity for security force violence in the Papuan provinces, with stalled investigations leaving victims without justice. Despite reports filed by families and lawyers, and pledges for transparent investigations, cases of alleged extrajudicial killings and abuses remain in legal limbo, obstructing criminal accountability. This ongoing issue underscores a significant human rights and intelligence challenge in the region.

Geopolitical Impact and Regional Dynamics

Indonesia's activities during this period significantly reinforced its role as a key player in regional and global diplomacy. The hosting of "Exercise Trident Resolve 2026" in Banten, involving 19 nations, showcased Indonesia's leadership in multilateral security cooperation, particularly in humanitarian assistance and disaster relief. This exercise, integrating cybersecurity and military medicine, strengthens trust and interoperability among ASEAN members and dialogue partners, including major powers like the US, China, and Russia. Such initiatives contribute to regional stability by building collective capacity for non-traditional security threats.

Diplomatically, Indonesia's strong presence at the UN General Assembly, led by Foreign Minister Sugiono, highlighted its commitment to a "free and active" foreign policy. By advocating for UN reform, the voice of the Global South, and particularly the Palestinian cause, Indonesia positioned itself as a bridge-builder and a champion for developing countries. The walkout during Israeli Prime Minister Netanyahu's speech further solidified Indonesia's stance on the Israeli-Palestinian conflict, aligning it with a broader group of nations critical of Israel's actions in Gaza. This assertive diplomacy, coupled with its bid for a non-permanent seat on the UN Security Council for 2029-2030, demonstrates Indonesia's ambition to increase its influence in global governance.

Relations with major powers saw nuanced developments. The Major Defense Cooperation Partnership with the United States, highlighted by the recently concluded "Super Garuda Shield 2026," deepens military ties and cooperation on modernization and technology. This partnership is crucial for Indonesia's defense capabilities and aligns with the US's Indo-Pacific strategy. Concurrently, Indonesia's participation in ADMM-Plus exercises alongside China and Russia, and its emphasis on domestic resilience at the BRICS Summit (though outside the reporting period, its policy implications are current), reflect its multipolar foreign policy approach, seeking engagement with various global powers without being solely aligned with one bloc. The arrival of the Italian aircraft carrier also signals expanding defense cooperation with European partners.

The significant financial losses from cyberattacks and the focus on national cyber resilience, as discussed at the IndoSec 2026 summit, underscore a growing vulnerability that could have broader geopolitical implications if critical infrastructure is compromised. International cooperation in cybersecurity, as seen in "Trident Resolve 2026" and counter-terrorism dialogues with Australia, is vital for mitigating these transnational threats.

Military and Defense Analysis

Indonesia's military and defense posture during this period reflects a continued emphasis on modernization, enhanced interoperability, and a robust response to both traditional and non-traditional security challenges. The conclusion of "Super Garuda Shield 2026" and the establishment of a Major Defense Cooperation Partnership with the United States signify a strategic shift towards developing advanced defense measures and next-generation technologies. This partnership aims to improve troop training, maintenance, repair, and overhaul capabilities, directly contributing to the readiness of the Indonesian National Armed Forces (TNI).

The hosting of "Exercise Trident Resolve 2026" demonstrates Indonesia's commitment to developing its capabilities in humanitarian assistance and disaster relief (HADR), military medicine, and cybersecurity. The participation of 19 countries, including major military powers, provides invaluable experience for the TNI in coordinating large-scale, multinational responses to complex emergencies, such as natural disasters. This focus on non-traditional security threats complements Indonesia's conventional defense modernization, ensuring a more comprehensive security apparatus. The arrival of the Italian aircraft carrier ITS Giuseppe Garibaldi-551 further indicates Indonesia's efforts to enhance its maritime capabilities and expand defense cooperation beyond traditional partners.

While specific defense spending trends for this precise period were not detailed, the ongoing modernization programs, including the acquisition of strategic military platforms like Rafale fighter jets and advanced radar systems earlier in 2026, suggest a sustained commitment to increasing defense expenditure. The emphasis on strengthening domestic resilience and self-reliance, as articulated by President Prabowo Subianto at the BRICS Summit, also implies a long-term strategy to reduce dependency on foreign military aid and foster a stronger domestic defense industry. The persistent security challenges in West Papua, characterized by impunity for security force violence, highlight the need for continued internal reforms and oversight within the TNI and Polri to ensure human rights are upheld during security operations.

Outlook and Forecast

Short-term trends (1-3 months):
In the immediate future, Indonesia will likely continue its active diplomatic engagement following the UN General Assembly, particularly in advocating for the Palestinian cause and pursuing its UN Security Council bid. The momentum from "Exercise Trident Resolve 2026" will likely translate into further regional cooperation initiatives, especially in disaster response and cybersecurity, as participating nations analyze lessons learned. Domestically, the focus on cybersecurity will remain high, with ongoing efforts to implement strategies discussed at IndoSec 2026 to counter the significant financial losses from cyberattacks. The authorities will remain vigilant regarding potential social unrest, particularly in the wake of "Black September" rumors, though the immediate threat appears contained.

Critical flashpoints and risk areas:
One critical flashpoint remains West Papua, where the persistent issue of impunity for security force violence could exacerbate tensions and fuel further unrest. The ongoing lack of accountability risks undermining public trust and potentially drawing international scrutiny. Another significant risk area is cybersecurity, given the reported US$6.2 billion in losses this year and the increasing sophistication of threats. A major cyberattack on critical infrastructure could have severe economic and national security repercussions. Maritime security in the Java Sea and other Indonesian waters will continue to be a concern, highlighted by the recent ferry disaster, necessitating enhanced safety regulations and enforcement.

Indicators to monitor:
Key indicators to monitor include the progress of investigations into security force violence in West Papua and any new reports of human rights abuses. In cybersecurity, observe the effectiveness of new national strategies and the frequency and impact of reported cyber incidents. On the diplomatic front, track Indonesia's progress in its UN Security Council bid and its continued engagement on global issues, particularly the Israeli-Palestinian conflict. Domestically, monitor any resurgence of large-scale protests or social unrest, especially around sensitive dates or political developments. Also, observe any new defense acquisitions or joint military exercises that could signal shifts in Indonesia's strategic partnerships.

Strategic recommendations:
Indonesia should prioritize strengthening its legal and judicial mechanisms to address impunity in West Papua, ensuring transparent investigations and accountability for security force actions. This would help de-escalate tensions and improve human rights records. To counter the escalating cyber threat, a multi-pronged approach is recommended, including increased investment in cybersecurity infrastructure, enhanced public-private partnerships, and robust international cooperation on threat intelligence sharing and capacity building. Furthermore, Indonesia should continue to leverage its "free and active" foreign policy to promote multilateralism and regional stability, actively engaging with all major powers while safeguarding its national interests. Domestically, continuous monitoring and proactive engagement with civil society are crucial to manage potential social unrest and address underlying grievances.

Sources

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