The escalation of the conflict between Iran and the US-Israeli coalition has caused a multidimensional crisis that has a significant impact on Indonesia, requiring it to develop a maritime defense strategy that is in line with international law and ensures national resilience.
This event not only fundamentally changed the security landscape of the Middle East but also triggered a global political realignment whose impacts are still felt today. Further, as the world’s largest archipelagic nation, situated between two oceans, Indonesia is currently facing the direct and indirect impacts of this crisis. This article discusses the implications of the Hormuz conflict on Indonesia’s national resilience and formulates an appropriate defence strategy in the Indonesian Archipelagic Sea Lanes (ALKI), while adhering to the international legal framework.
The Impact of the Strait of Hormuz Blockade on Indonesia
The Gulf conflict put significant pressure on the Indonesian economy through soaring oil, gas, and fertilizer prices. In April 2026, oil prices surpassed US$120 per barrel, triggering a surge in energy subsidies to more than 210 trillion rupiah beyond initial projections. Logistics costs rose by approximately 30%, disrupting supply chains and driving inflationary pressures. The projected budget deficit of 2.7% of GDP, assuming oil at US$70 per barrel, now faces the risk of ballooning significantly, potentially exceeding the 3% safety threshold.
Indonesia’s bilateral relations with Iran reached a low point when the Iranian government detained two Indonesian oil tankers, the VLCC Pertamina Pride and the PIS Gamsunoro, in the Strait of Hormuz. While neighbouring countries in Southeast Asia, like Malaysia and Thailand, received priority permits, Indonesia’s maritime assets were hampered. This incident reflects the accumulation of bilateral tensions, including a previous, protracted dispute over the seizure of the Iranian vessel MT Arman 114 in Natuna waters in 2023.
Meanwhile, from an international legal perspective, the support of Australian warships delivering military aid to the United Arab Emirates via ALKI could potentially be a legitimate target for Iran under the laws of war, given that the cargo substantially contributes to the military efforts of one of the conflicting parties. This puts Indonesia in a precarious position as a neutral country.
ALKI’s Strategic Vulnerability: Fundamental Differences with the Strait of Hormuz
It is important to understand that Indonesia’s position differs fundamentally from Iran’s. Indonesia is an archipelagic state that has ratified UNCLOS 1982 through Law No. 17 of 1985 and established the ALKI through Government Regulation No. 37 of 2002, thus legally obligating it to guarantee the right of archipelagic sea lanes passage for foreign vessels. This is fundamentally different from Iran, which has not ratified UNCLOS. Indonesia’s unilateral closure of the ALKI would have immediate repercussions and be categorized as a serious violation of international law.
Geographically, the Strait of Hormuz is a single, narrow gateway with an effective navigational lane of only about 3 kilometres. In contrast, Indonesia has three extensive ALKI channels, i.e., South China Sea-Sunda Strait (ALKI I), Makassar Strait-Lombok Strait (ALKI II), and Maluku Sea-Ombai Strait (ALKI III). It is approximately 40% of global trade that passes through Indonesian waters.
Narrow chokepoints are inherently vulnerable to military escalation due to limited maritime manoeuvring space, which increases the risk of miscalculation. If Indonesia unilaterally restricts access to the Indonesian Sea, major user countries such as Japan, China, and India could potentially optimize their naval presence to ensure freedom of navigation, which would increase the risk of unforeseen incidents in Indonesian waters.
The Indonesian government’s most appropriate strategy is to strengthen defensive sea control, through the ability to monitor, identify, and respond to any military threats without unnecessarily impeding legitimate civilian shipping activities. This approach aligns with Indonesia’s independent and active foreign policy and the principles of UNCLOS.
The Indonesian Coordinating Ministry for Political and Security Affairs has developed the National Maritime Security Index as a data-driven policymaking instrument for objectively formulating and evaluating maritime security policies. Strengthening the IKLN (National Maritime Security Index) in East Kalimantan (ALKI II) and East Nusa Tenggara (ALKI III) includes patrol and monitoring capacity, maritime crime control, and prevention of territorial water pollution.
Amid pressure to take sides, Indonesia demonstrated a prudent multi-alignment strategy. In April 2026, the Indonesian government simultaneously signed the Major Defence Cooperation Partnership (MDCP) with the US at the Pentagon while President Prabowo Subianto simultaneously held a marathon meeting with Russian President Vladimir Putin in Moscow to secure supplies of Russian crude oil at a significant discount of around US$59 per barrel.
Meanwhile, the signing of the MDCP grants Indonesia access to advanced technology, including undersea systems and asymmetric capabilities, without a joint defence clause that could drag Indonesia into international conflict. However, this is a smart balance, securing security guarantees from the West and energy from the East.
Strengthening Maritime Domain Awareness
Optimizing maritime domain awareness through the integration of coastal radar, automatic identification systems, maritime air patrols, and underwater surveillance is a priority. The Coordinating Ministry for Political, Legal, and Security Affairs is encouraging the acceleration of bathymetric mapping and hydrographic data in ALKI III as a strategic element supporting shipping safety and maritime security.
The empowerment of coastal communities and fishermen as the eyes and ears within the framework of the Indonesian Total People’s Defence and Security System needs to be revitalized and optimized to enhance civilian resilience in facing crises in Indonesian waters.
The Iran-US-Israel conflict and the blockade of the Strait of Hormuz can be perceived as the disruption of maritime chokepoints certainly has far-reaching implications for the global economy’s growth and Southeast Asian regional stability. For Indonesia, the ALKI closure scenario is unjustifiable under international law and would be counterproductive to national interests. The appropriate and feasible strategy is to strengthen defensive sea control, boost maritime surveillance capacity, optimize multi-alignment diplomacy that maintains strategic autonomy, and revitalize coastal-community-based national resilience.
This approach is expected to help Indonesia maintain a balance of power between sovereignty and international responsibility, strengthen its reputation as a rule-of-law state consistent with the implementation of a rule-based order, and ensure that national defence interests do not have to sacrifice domestic economic stability amidst the ongoing global geopolitical turmoil.
Hendra Manurung is currently Assistant Professor of International Relations at the Department of Defence Diplomacy, Faculty of Defence Strategy, Republic of Indonesia Defence University
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