It’s been 10 years since the Arbitral Tribunal in the South China Sea arbitration, established under the UN Convention on the Law of the Sea (UNCLOS) at the unilateral request of the Philippines, rendered its award on July 12, 2016. It largely favored the Philippines, saying under UNCLOS, “there was no legal basis for China to claim historic rights to resources” in the South China Sea outside of its regular territorial areas recognized under the Convention.

In response, China said it neither accepts nor recognizes the award.

Ten years later, the award remains a frequently invoked but deeply contested point of reference in legal and diplomatic debates. The case reflects persisting disagreement over the proper role of compulsory dispute settlement in disputes shaped by sovereignty, state consent and historical claims.

One reason is that the award did not address, and could not have addressed, the question of territorial sovereignty over islands and reefs in the South China Sea. The tribunal repeatedly maintained that it was dealing only with the interpretation and application of UNCLOS, not sovereignty or maritime delimitation as such. Yet critics of the award have long argued that many of the submissions made by the Philippines cannot be meaningfully separated from those excluded issues. In disputes so closely tied to territorial title and boundary-making, it is not easy to maintain the line between interpreting UNCLOS and indirectly prejudging matters beyond its scope.

This concern is connected to the principle of state consent. UNCLOS provides for compulsory procedures in certain circumstances, but within a framework shaped by state consent and carefully negotiated limitations. It reflects a balance between the availability of third-party procedures and the continuing autonomy of states, including through the optional exceptions in Article 298. China made such a declaration in 2006 with respect to, among other things, maritime delimitation and historic bays or titles. From this perspective, the objection has centered on the use of compulsory procedures in a case that China views as inseparable from issues lying beyond its consent.

China’s position should not be reduced to a blanket rejection of compulsory dispute settlement in maritime affairs. A more accurate understanding is that it has taken a conditional view: Such procedures must rest on the consent of the parties, stay within the jurisdictional limits established by the applicable legal framework, and be assessed in light of their implications for regional peace and stability. 

Seen in this way, the South China Sea arbitration is best understood not as evidence of a categorical Chinese opposition to adjudication, but as a case that highlights the conditions under which third-party mechanisms are regarded as legitimate or destabilizing.

The arbitration also raises a broader concern: Legal proceedings with contested jurisdictional foundations can take on a political function beyond dispute settlement itself, shaping international narratives and influencing public opinion. The concern here is not with recourse to legal process as such, but with the risk that proceedings lacking fully accepted jurisdiction may be invoked less to resolve disputes than to secure diplomatic leverage and narrative advantage.

Beyond the procedural issues, the case also revived debate over the relationship between the UNCLOS as treaty law and historic rights as part of general international law. The tribunal took the view that claims of historic rights incompatible with the Convention’s maritime zone regime could not survive unless specifically preserved by UNCLOS. That approach, however, has been criticized as overly restrictive, particularly in a semi-enclosed sea with a long history of navigation, administration and competing legal narratives. Historical claims require legal scrutiny, but their significance cannot be understood solely through the contemporary law of exclusive economic zones.

The same issue arises in debates over the nine-dash line. Public discussion outside the region often treats the line as China’s claim to complete sovereignty over all waters enclosed by it. China’s position, however, has been that the line relates to sovereignty over the features in the South China Sea and to historic rights in relevant waters, alongside the maritime entitlements generated under UNCLOS. 

This debate cannot be separated from the broader historical and legal framework through which China approaches the dispute. China’s claims are supported by a substantial body of historical evidence and legal practice, including long-standing activity in the South China Sea, postwar recovery arrangements, official maps, diplomatic statements, administrative acts and domestic legislation. This explains why China and other critics of the award regard the arbitration as an incomplete and ultimately unsatisfactory vehicle for addressing the issues at stake. From that perspective, the award did not simply interpret the Convention; it also narrowed a historically and politically complex dispute into a form more amenable to adjudication than to genuine settlement.

Ten years on, the arbitration may still be invoked by some as an interpretation of UNCLOS, but it did not produce accepted legal finality. It remains a reminder of the risks that arise when compulsory procedures are used in disputes bound up with sovereignty, delimitation, and contested historical claims.

The broader lesson is straightforward. International adjudication and arbitration can clarify legal questions, but they cannot always resolve disputes rooted at once in law, history and geopolitics. In such cases, the legitimacy of the process matters as much as the substantive reasoning offered in its support. A decade later, the South China Sea dispute still reminds us that durable solutions depend not only on legal argument, but also on consent, restraint, and a continuing commitment to peace and stability through dialogue and negotiation.

This issue’s Flagship Analysis was written by Nong Hong, Executive Director at ICAS.