Introduction
Few arbitral awards in the history of international law have generated as much controversy, legal scholarship, and geopolitical consequence as the South China Sea Award of 12 July 2016, rendered by a tribunal constituted under Annex VII of the United Nations Convention on the Law of the Sea in the case Philippines v. China (PCA Case No. 2013-19). The tribunal’s sweeping holdings, affirming the Philippines’ rights under UNCLOS in its EEZ, invalidating China’s historical rights claim within the nine-dash line as having no basis in international law, and characterising China’s construction activities on low-tide elevations as unlawful, landed with the force of a jurisprudential earthquake. And yet, nearly a decade later, China’s nine-dash line claim is as prominently displayed on its official maps as ever, its artificial island facilities in the Spratly Islands remain operational and militarised, and the South China Sea continues to be a zone of contested sovereignty, rival maritime patrols, and periodic dangerous confrontations between Chinese coast guard vessels and the forces of Philippines, Vietnam, Indonesia, and others.
The South China Sea arbitration exemplifies one of international law’s most enduring and uncomfortable truths: a tribunal can declare the law with precision and authority, but it cannot compel compliance by a state that has decided, for reasons of domestic politics, strategic calculation, and great power self-perception, that it will not be bound. This article examines the Award’s principal holdings, the UNCLOS enforcement framework’s limitations, the militarisation of the South China Sea, the emerging maritime coalition dynamics involving India, and the Philippines’ renewed assertiveness under President Marcos Jr.
Legal Framework
UNCLOS, adopted in 1982 and entered into force in 1994, establishes a comprehensive framework for ocean governance. Its provisions on dispute settlement (Part XV) are notably sophisticated compared to earlier international maritime law: states parties are required to submit disputes concerning the interpretation or application of UNCLOS to binding dispute resolution, with a choice of forum including the International Tribunal for the Law of the Sea (ITLOS), the ICJ, or arbitration under Annex VII or Annex VIII. This compulsory jurisdiction provision is one of the strongest in any multilateral treaty, applying without requiring additional consent of the respondent state.
China ratified UNCLOS in 1996 but made declarations under Article 298 excluding certain categories of disputes from compulsory procedures, including disputes regarding delimitation of maritime boundaries and disputes concerning “historic bays or titles.” China argued that the Philippines’ claims fell within these excluded categories and that the Annex VII tribunal therefore lacked jurisdiction. The tribunal disagreed on jurisdiction, finding that the Philippines had framed its claims to avoid the Article 298 exclusions: rather than asking the tribunal to delimit boundaries, the Philippines asked whether China had any legal rights at all within the nine-dash line under UNCLOS, and whether certain features (reefs, rocks, low-tide elevations) were entitled to generate EEZ entitlements.
The nine-dash line is a U-shaped series of dashes on Chinese official maps that encloses approximately ninety percent of the South China Sea. China’s legal characterisation of its claims within the nine-dash line has never been entirely clear: Chinese officials have variously described it as a claim to historical rights over resources, a claim to historic waters (analogous to internal waters), or a claim to sovereign rights over the features within the line and their surrounding waters. The tribunal held that UNCLOS, as a comprehensive and unified regime governing maritime entitlements, left no room for historical rights over resources in waters that UNCLOS assigns to other states’ EEZs or to the high seas. Any Chinese maritime entitlements must be derived from the land features it occupies, measured in accordance with UNCLOS rules.
Key Holdings of the 2016 Award
The tribunal’s principal findings addressed three clusters of issues. On maritime entitlements, the tribunal found that none of the South China Sea features occupied by China constitute “islands” under UNCLOS Article 121(1) (features capable of sustaining human habitation or economic life of their own) that would generate full EEZ and continental shelf entitlements. The Spratly Islands, Scarborough Shoal, and other features are at best rocks under Article 121(3) (entitled only to a twelve-nautical-mile territorial sea) or low-tide elevations (generating no maritime zones). This finding, if implemented, would dramatically reduce the sea area within which China has any UNCLOS-based maritime rights.
On China’s activities, the tribunal found that China had violated the Philippines’ sovereign rights in its EEZ by interfering with Philippine fishing and petroleum exploration, constructing artificial islands, and failing to prevent Chinese fishermen from harvesting endangered species. On the artificial islands, the tribunal found that China’s dredging and construction on several reefs had destroyed coral reef ecosystems and had potentially caused irreversible harm to the marine environment in violation of UNCLOS provisions.
China issued a declaration on the day of the Award stating that the Award is “null and void and has no binding force.” China has maintained this position consistently, declining to engage in any compliance and characterising the arbitral proceedings as a “political farce” disguised as legal process. Beijing’s position rests on the argument that the tribunal lacked jurisdiction (which the tribunal itself rejected after extensive deliberation), that the Philippines’ submission was an attempt to use UNCLOS to litigate what are actually sovereignty disputes, and that the Award reflects a Western legal order that China did not consent to and considers biased against developing nations’ historical claims.
Enforcement Gap and Alternative Mechanisms
UNCLOS provides no enforcement mechanism for non-compliance with arbitral awards. Article 296 states that decisions of courts and tribunals shall be complied with by the parties, but there is no mechanism for compelling compliance beyond bringing the matter to the Security Council under Article 94(2) of the UN Charter (which applies to ICJ judgments), a mechanism unavailing against China given its veto. Nor does UNCLOS provide for any collective sanctions mechanism against non-complying states.
The enforcement gap has led states and analysts to identify alternative mechanisms for operationalising the Award’s findings. Freedom of Navigation Operations (FONOPs) conducted by the United States Navy, asserting navigation rights in waters claimed by China, have been characterised by the US as consistent with the tribunal’s findings and have continued regularly since 2016. FONOPs are not a legal enforcement mechanism but a form of state practice designed to prevent Chinese claims from consolidating into customary law through acquiescence. The logic is that if all other states navigated as if China’s claims were valid, they would gradually harden into accepted custom; FONOPs maintain the assertion that the claims are invalid.
The UK, Australia, Canada, France, and Germany have all conducted or supported freedom of navigation operations in the South China Sea since 2016. India has maintained a more ambiguous position: India supports UNCLOS and the rule of law in maritime affairs, and its Navy regularly transits the South China Sea on lawful passage, but India does not formally characterise its transits as FONOPs asserting rights against specific Chinese claims. India’s position reflects sensitivity to the Sino-Indian relationship and a preference for managing the issue diplomatically rather than through military signalling.
Contemporary Issues and Analysis
The situation in the South China Sea has deteriorated rather than improved since the 2016 Award. China has continued construction and militarisation of artificial islands, installing radar systems, aircraft hangars, weapon systems, and military facilities on Mischief Reef, Fiery Cross Reef, and Subi Reef among others. These installations have fundamentally altered the strategic balance of the region, giving China the ability to project air power and maritime forces far beyond its continental coast.
The most immediate flashpoint has been the confrontations between Chinese Coast Guard vessels and Philippine supply boats serving the BRP Sierra Madre, a deliberately grounded ship on Ayungin Shoal (Second Thomas Shoal) that the Philippines maintains as a de facto military outpost within its UNCLOS EEZ. Chinese coast guard vessels have used water cannons, deployed acoustic devices, and conducted manoeuvres described by the Philippines as dangerous and illegal. These confrontations have included incidents of injury to Philippine Coast Guard personnel and damage to Philippine vessels, raising the question of whether China’s conduct constitutes unlawful force against Philippine sovereign rights under UNCLOS.
Under President Ferdinand Marcos Jr., the Philippines has adopted a markedly more confrontational posture than under his predecessor Rodrigo Duterte, who had pursued a policy of accommodation toward China in exchange for investment promises that largely did not materialise. Marcos’s government has made the South China Sea situation much more publicly visible through policy of releasing media documentation of Chinese conduct, reinvigorating the US-Philippines alliance (including the expansion of US military base access under the Enhanced Defence Cooperation Agreement), and invoking the 2016 Award in diplomatic statements.
India’s Position and Maritime Interests
India’s engagement with the South China Sea issue is structured by several overlapping considerations. India’s support for UNCLOS as the governing framework for maritime law, including its entitlements in its own Arabian Sea and Bay of Bengal EEZs, makes it consistent for India to support UNCLOS-based resolution of South China Sea disputes. India has repeatedly stated that disputes must be resolved in accordance with international law, including UNCLOS, and has invoked the 2016 Award’s legitimacy in the UN General Assembly context.
At the same time, India is not a party to the dispute and has no direct territorial interest in the contested features, though Indian commercial shipping passes through South China Sea routes on which any restrictions on freedom of navigation would have serious economic consequences. India’s maritime doctrine acknowledges the South China Sea as within India’s strategic area of interest, and India’s Project Mausam and SAGAR (Security and Growth for All in the Region) initiatives reflect India’s ambition to position itself as a leading maritime security provider in the Indian Ocean and beyond.
The QUAD (Quadrilateral Security Dialogue), comprising India, the United States, Japan, and Australia, has increasingly focused on maritime domain awareness in the Indo-Pacific, including the South China Sea area. The Maritime Domain Awareness for Trade Indo-Pacific (MDAT-IOP) programme and joint naval exercises are among the QUAD’s operational maritime deliverables. India’s participation in QUAD maritime activities implicitly supports the freedom of navigation framework that China’s South China Sea posture challenges, even if India declines to explicitly frame this as opposition to China’s nine-dash line claims.
The India-China bilateral relationship adds further complexity. Following the 2020 Galwan Valley clash in which Indian and Chinese soldiers were killed in a border confrontation, India-China relations entered a period of sustained tension. India has been more willing to participate in multilateral maritime frameworks that constrain China, while maintaining formal bilateral dialogue channels. India’s ITLOS case (under the India-Bangladesh Maritime Boundary arbitration, 2014) demonstrates India’s own willingness to use UNCLOS compulsory dispute settlement when its own rights are at stake, a fact that makes India’s reluctance to formally endorse the Philippine Award notable.
Comparative Perspective: ITLOS Advisory Opinion on Fisheries
ITLOS’s 2024 Advisory Opinion (requested by the Commission of Small Island States on Climate Change and International Law) confirmed that UNCLOS imposes specific, enforceable obligations on states to reduce greenhouse gas emissions that cause marine environment damage. While the Advisory Opinion was primarily climate-focused, it affirmed the general ITLOS position that UNCLOS provisions are broadly applicable and enforceable through its advisory and contentious jurisdiction. This reinforces the UNCLOS framework’s legal vitality even in the South China Sea context, where that framework has been defied by China.
Practical and Policy Implications
The South China Sea situation has significant implications for the international rule of law in maritime affairs. If China’s non-compliance with the Award produces no meaningful consequences while China continues to expand its factual control over contested features, the message to other states is that sufficiently powerful states can defy international arbitral awards without consequence. This creates perverse incentives for revisionist states and undermines the compulsory dispute settlement architecture that makes UNCLOS’s comprehensive maritime governance framework credible.
The alternative, generating consequences for non-compliance through collective action, has been partial. The G7 and the EU have issued statements affirming the Award’s legal binding character and calling on China to comply, but have not imposed specific consequences. ASEAN, whose member states include most of the directly affected parties (Vietnam, the Philippines, Malaysia, Brunei, and Indonesia all have overlapping claims), has been unable to adopt a collective position because China’s influence within ASEAN (particularly over Cambodia and Laos) has consistently prevented consensus statements on the South China Sea.
Suggestions and Reforms
The UNCLOS enforcement gap is a fundamental structural problem that requires both treaty-level reform and pragmatic interim measures. At the treaty level, the UNCLOS Annex VII arbitration rules should be supplemented by a mechanism for collective non-recognition of assertions of sovereignty or sovereign rights that are inconsistent with arbitral awards, analogous to the UN Charter’s obligation to support ICJ judgments. States parties could commit, as a matter of treaty obligation, not to recognise de facto or de jure claims that have been invalidated by UNCLOS arbitration.
In the interim, the most effective mechanisms for limiting the consequences of China’s non-compliance are continued FONOPs and coalition maritime presence, reinforcement of the Philippines’ and Vietnam’s capacity to assert and defend their UNCLOS entitlements, and sustained economic and diplomatic costs for China’s militarisation conduct through multilateral statements, targeted technology controls, and investment in alternative shipping infrastructure.
India should consider explicit endorsement of the 2016 Award as legally binding in its official communications, which would be consistent with India’s stated positions on UNCLOS and international law without requiring India to take a military posture in South China Sea waters. Such a statement would reinforce the award’s normative authority without the escalation risks of FONOPs.
Conclusion
The South China Sea arbitration Award is a landmark in the development of international law, confirming the breadth of UNCLOS compulsory jurisdiction and the legal invalidity of historical rights claims inconsistent with the Convention. Its legacy, however, is currently more cautionary than triumphant: it demonstrates that international legal declarations, however authoritative, do not automatically produce compliance from states with the power and will to defy them. The task for the international community is to make the costs of non-compliance sufficiently high, through collective diplomatic, economic, and legal pressure, that even powerful states calculate that compliance is preferable to continued defiance. This task requires precisely the kind of sustained multilateral coalition-building that has been difficult to assemble against China’s economic and political weight, but the stakes, both for the rule of law and for the maritime freedom upon which global commerce depends, could not be higher.
