What are the primary objectives for Indonesia as the co-chair for the Naval Warfare Workstream of the Global IHL Initiative?

Indonesia pursues three principal objectives.

First, to facilitate discussion among States on the legal relationship between the law of naval warfare, IHL and the 1982 United Nations Convention on the Law of the Sea [UNCLOS]. These frameworks emerged in different historical contexts; UNCLOS, adopted decades after the Hague and Geneva regimes, was not drafted with armed conflict at sea specifically in mind. This temporal gap raises questions that merit careful legal consideration.

Second, to identify and address existing legal gaps affecting coastal and archipelagic States, including Indonesia. These include issues such as:

• • the definition and breach of maritime neutrality;

• • security implications arising from belligerent warships transiting exclusive economic zones [EEZs] or archipelagic sea lanes; and

• • the broader duty of States to respect and ensure respect for IHL.

Third, to strengthen considerations of humanity in armed conflict at sea, particularly regarding the protection of civilians, civilian infrastructure and the marine environment. For Indonesia, participating in the Global IHL Initiative is natural. As the world’s largest Archipelagic State located at the crossroads of the Indian and Pacific Oceans, Indonesia has a strong interest in ensuring that the legal framework governing the oceans remains coherent and effective, including in situations of armed conflict.

Can you describe the workstream’s most discussed issues?

State consultations have consistently focused on several key clusters of issues.

First, the interaction between UNCLOS and the law of naval warfare, particularly how peacetime navigational regimes operate alongside wartime rules governing hostilities and neutrality.

Second, the protection of civilians and civilian infrastructure at sea, as well as topics such as dual-use assets, merchant vessels, ports, and submarine communication cables.

Third, the protection of the marine environment during armed conflict, including whether environmental obligations, such as the principle of “due regard”, continue to apply meaningfully during hostilities.

Fourth, issues of maritime neutrality, including the rights and obligations of neutral States, particularly neutral archipelagic States, when belligerent naval forces operate in nearby maritime zones.

Fifth, the implications of emerging technologies, including unmanned underwater vehicles, lethal autonomous weapons systems and the manipulation of maritime automatic identification systems. These developments raise complex and operational questions that existing frameworks have not anticipated.

Why is it particularly important to consider the law of naval warfare today?

Recent events demonstrate the urgency of examining this field more closely. Armed incidents affecting maritime trade routes – take, for example, the outbreak of hostilities in the Middle East, particularly in the Strait of Hormuz, the Black Sea and the Red Sea – illustrate how naval hostilities can disrupt global supply chains and affect civilian populations far beyond the immediate conflict zone. Several factors underscore the need for renewed attention.

First, naval warfare has evolved significantly. Modern conflicts involve hybrid threats, non-State actors, autonomous systems, cyber operations and digital infrastructure – developments not contemplated when many existing legal instruments were drafted.

Second, the codification of maritime zones under UNCLOS occurred long after the classical law of naval warfare was formulated. This raises questions about the relationship between belligerent rights and the sovereign rights of coastal States.

Third, civilian infrastructure such as submarine cables and pipelines has become essential to global connectivity; determining the legal status of such infrastructure during armed conflict is therefore increasingly important.

Fourth, recent conflicts highlight continued challenges in ensuring compliance with the fundamental principles of the law of armed conflict, particularly the protection of civilians.

Fifth, countries like Indonesia, whose economies depend heavily on maritime trade, have a strong interest in ensuring that navigation remains secure and governed by clear legal rules.

In short, international law must continually be clarified and interpreted to remain effective in addressing the realities of contemporary armed conflict at sea.

The majority of the rules comprising the law of naval warfare are customary in nature. As a practitioner advising a State, how do you navigate this?

From Indonesia’s standpoint, the most reliable approach is to anchor State practice firmly in binding treaty obligations, particularly the Geneva Conventions and UNCLOS, while interpreting customary norms consistently with those instruments. Identifying customary international law is often complex, particularly when State practice varies, and for many developing countries, an important question arises: who shaped these norms, and to what extent were all States involved in their formation? While initiatives such as the ICRC Customary Law Study provide valuable guidance, greater clarity could be achieved through more consolidated legal instruments that codifies or further develops relevant norms.

Do you foresee any meaningful prospects for new treaties in the field of naval warfare? If not, in order to keep the law fit for purpose, which avenues for normative development would you suggest?

A new treaty framework may not be imminent, but it may ultimately prove necessary. Key areas remain insufficiently addressed in existing instruments such as the Hague Regulations of 1907 and the Geneva Conventions, and while manuals such as the San Remo and Newport Manuals provide useful guidance, they remain non-binding. Several emerging issues illustrate these gaps:

• • cyber operations and their relationship to the law on the use of force;

• • the legal status of undersea infrastructure such as submarine cables;

• • the continued relevance of classical prize law, as well as many legal questions surrounding blockade and contraband;

• • belligerent military operations within coastal States’ EEZs; and

• • the application of neutrality principles within archipelagic sea lanes.

These areas represent what might be described as “uncharted legal territory”, where further clarification and normative development would be beneficial.

Indonesia is one of the few States possessing a hospital ship. What prompted Indonesia to acquire such a ship, and how can this reinforce the legal protection of the wounded, sick and shipwrecked at sea?

In 2022, Indonesia acquired the KRI dr. Radjiman Wedyodiningrat in recognition of our geographical reality as an archipelagic State. Hospital ships provide floating medical facilities capable of supporting military operations, humanitarian missions and disaster relief efforts, and their mobility allows rapid response across Indonesia’s vast maritime territory and in support of regional humanitarian needs. The KRI dr. Radjiman Wedyodiningrat’s recent deployment in a humanitarian assistance mission on the coast of the Gaza Strip reflects Indonesia’s broader commitment, consistent with our constitutional mandate, to contribute to international peace and the protection of humanity.

How do you see the role of UNCLOS in the event of an international armed conflict at sea?

UNCLOS was conceived primarily as the “constitution of the ocean” for peacetime governance. It was not drafted specifically to regulate armed conflict. However, this does not mean that its provisions automatically cease to apply during hostilities – navigational rights, environmental obligations and maritime zone regimes remain relevant. The real challenge lies in understanding how UNCLOS interacts with IHL and the law of naval warfare; in Indonesia’s view, these bodies of law must be interpreted together, rather than in isolation. Their intersection is particularly evident in issues such as:

• • navigational rights during armed conflict;

• • environmental protection obligations;

• • the status of maritime zones in wartime; and

• • the balance between coastal State rights and the duties of neutral States.

The concrete example of the recent outbreak of hostilities affecting global sea lanes in the Strait of Hormuz features all of these legal issues combined.

Many scholars have said that the principle of “due regard” for the rights of third States, as enshrined in UNCLOS, is the intersection of IHL and the law of naval warfare with UNCLOS. States have interpreted this as essentially allowing third States to conduct hostilities in the EEZ of a coastal State. In carrying out their legitimate rights, they have to give due regard to the rights of neutral States.

What major legal issues does Indonesia see for the interplay between the law of the sea and the law of naval warfare for archipelagic States?

For archipelagic States, several issues are particularly significant. One key concern is the non-suspendable nature of archipelagic sea lanes passage: if opposing belligerent forces use the same sea lanes simultaneously, the waters of a neutral archipelagic State could inadvertently become a theatre of military activity. Environmental protection is another important issue, as both UNCLOS and IHL impose obligations related to the protection of the environment.

Questions also arise regarding maritime neutrality, including the duty of neutral States to prevent their territory from being used in ways that advantage one belligerent. And finally, the practice of declaring war risk zones or exclusion zones raises concerns when such zones intersect with areas under the sovereignty or jurisdiction of archipelagic States.

Throughout history, naval blockades have caused considerable suffering to civilians. What aspects of the applicable legal framework could be clarified?

The discussions throughout Workstream 7 emphasize the importance of protecting civilians, merchant vessels and civilian infrastructure. One issue concerns the territorial scope of blockades, particularly where they intersect with situations of military occupation. Another key issue is the humanitarian impact of blockades on civilian populations: while blockades remain a recognized method of warfare, their implementation must respect the fundamental principles of IHL, including proportionality and the prohibition of starvation of civilians as a method of warfare. These questions warrant further legal examination and clarification.

Do you see a role for international courts and arbitral tribunals in adjudicating the law of naval warfare?

International courts and tribunals play an increasingly important role. Disputes involving the interpretation of UNCLOS may be brought before bodies such as International Tribunal for the Law of the Sea or the International Court of Justice; in addition, international criminal tribunals contribute to accountability for violations of the laws of armed conflict. Judicial decisions and advisory opinions further contribute to the development and clarification of international law, including the law governing naval warfare.

Is there anything else you would like to share with the readers of the Review regarding naval warfare?

The central message is clear: the ocean must not become a legal grey zone during armed conflict. International law – not power – should govern conduct at sea.

For Indonesia, Workstream 7 represents both a legal and a moral effort. We advocate for coherence between UNCLOS, IHL and the law of naval warfare, ensuring that these frameworks operate together to protect civilians, safeguard the marine environment and uphold the principle of humanity. For archipelagic States such as Indonesia, the development of clearer rules in this area, particularly regarding maritime neutrality, remains an important priority.