The South China Sea Arbitration and Recent Maritime Incidents: Legal Significance in 2025

Written by Jomart Joldoshev as part of the International Courts Reporter Series

The 2016 Award in The South China Sea Arbitration (Philippines v. China) remains one of the most significant interpretations of the United Nations Convention on the Law of the Sea (UNCLOS). Although nearly a decade has passed, a series of maritime incidents in 2025, including encounters at Scarborough Shoal[1], increased patrols near Mischief Reef[2], and the ongoing deployment of coast guard and maritime militia vessels, have renewed attention to the Tribunal’s findings. These events have prompted a reassessment of how the Award continues to shape legal analysis in the region. Understanding the Award’s conclusions and their relevance to current events remains essential for states, practitioners, and policymakers assessing the evolving maritime environment.

A key issue resolved by the Tribunal was the legality of China’s claim to “historic rights” within the nine-dash line. The Tribunal held that UNCLOS provides a comprehensive system of maritime rights that leaves no room for additional claims not based on the Convention. This decision effectively invalidates the nine-dash line as a basis for claiming exclusive resource rights. For legal professionals, this part of the Award is crucial because it makes clear that claims must fit within the zone-based framework established by UNCLOS. As maritime activities continue to intensify, whether States respect the limits established by UNCLOS rather than broader historical claims remains a vital legal question for assessment.

The Tribunal also clarified the maritime rights created by specific features in the Spratly Islands[3]. After a thorough factual analysis, it was determined that several features, including Mischief Reef, are low-tide elevations within the Philippines’ exclusive economic zone, while others were classified as rocks that cannot generate exclusive economic zones or continental shelves. These classifications greatly limit the legal maritime claims available to states in the region. Because the legal status of these features directly affects which state has sovereign rights over surrounding waters, the Award provides important guidance for interpreting current maritime disputes. Activities near Mischief Reef or Subi Reef[4], for instance, must be evaluated based on these classifications, which still define the legal nature of the maritime zones where operational interactions occur.

Another key aspect of the Award concerned the parties’ conduct. The Tribunal found that China disrupted the Philippines’ sovereign rights by preventing fishing, blocking petroleum exploration, and limiting access to traditional fishing areas, including Scarborough Shoal. It also concluded that China caused environmental damage through dredging and large-scale land reclamation. These findings remain relevant as new incidents occur. Reports from 2025 describe situations similar to those addressed in the Award, such as the use of water cannons, close-quarters maneuvering, and the presence of maritime militia vessels, raising questions about whether current activities align with UNCLOS obligations regarding sovereign rights, environmental protection, and safety at sea. Although the Tribunal did not rule on sovereignty over land features, its analysis of conduct provides a continuing legal framework for assessing operational behavior.

Recent incidents reveal that the areas most affected are precisely those addressed in the 2016 Award. At Scarborough Shoal, which the Tribunal recognized as subject to traditional fishing rights for Filipino fishermen, reports of restricted access directly support the Tribunal’s conclusions. Similarly, because Mischief Reef was classified as a low-tide elevation within the Philippines’ exclusive economic zone, any construction, deployment of maritime forces, or interference with navigation in its vicinity must be assessed in light of the Philippines’ sovereign rights under UNCLOS. These incidents demonstrate that the Tribunal’s detailed findings continue to guide the analysis of whether State conduct respects the entitlements and obligations defined by the Convention.

International responses further demonstrate the Award’s ongoing legal significance. In 2025, several governments, including the United States, Japan, Australia, and members of the European Union, stated that the 2016 Award is an authoritative interpretation of UNCLOS. These statements do not create new legal obligations but strengthen international expectations for maritime conduct and show that States continue to rely on treaty-based dispute resolution. The Award’s reaffirmation underscores the importance of maintaining a rules-based maritime order, especially as increased patrols and operational encounters heighten the risk of escalation. For professionals advising on navigation, investment, fishing rights, or regional security, these official references underscore the Award’s role in shaping diplomatic and legal assessments.

The current developments highlight both the strengths and limits of international adjudication. The Award clarifies rights, duties, and the legal status of maritime zones. Yet its practical influence depends on State actions and geopolitical factors. Not all States accept or enforce the Award, yet it still guides legal analysis and remains key to understanding the South China Sea’s legal framework. Renewed focus on Scarborough Shoal and features in the Spratly Islands shows that the Tribunal’s decisions continue to shape discussions about lawful conduct under UNCLOS. Nearly ten years later, the 2016 Award remains a core tool for assessing maritime rights and duties and continues to provide essential guidance to practitioners and policymakers as maritime activities expand.

[1] A triangular group of rocks and reefs in the South China Sea, located approximately 124 nautical miles west of Luzon and within the Philippines’ exclusive economic zone, where the 2016 South China Sea Arbitration recognized traditional fishing rights, and which remains a frequent site of maritime incidents and access restrictions.

[2] A maritime feature in the Spratly Islands that the 2016 South China Sea Arbitration classified as a low-tide elevation located within the Philippines’ exclusive economic zone, meaning it cannot generate its own maritime zones, and any construction, deployment of maritime forces, or enforcement activity in its vicinity must be assessed in light of the Philippines’ sovereign rights under UNCLOS.

[3] A large group of reefs, rocks, and low-tide elevations in the South China Sea subject to overlapping claims by several States. In the 2016 arbitration, the Tribunal did not decide issues of sovereignty over land features but clarified the legal status of individual maritime features and their capacity to generate maritime zones.

[4] A maritime feature in the Spratly Islands that the 2016 South China Sea Arbitration classified as a low-tide elevation, which does not generate its own maritime zones under UNCLOS and whose legal relevance arises from its location within surrounding maritime entitlements.