Created: 08 April 2025
On 12 July 2016, an Arbitral Tribunal constituted under Annex VII of the United Nations Convention on the Law of the Sea (UNCLOS) rendered its Final Award in The South China Sea Arbitration (Republic of the Philippines v. People’s Republic of China), PCA Case No. 2013-19.1 Administered by the Permanent Court of Arbitration in The Hague, the Award remains one of the most consequential legal decisions in modern maritime law.
Its importance does not lie in resolving sovereignty disputes or redrawing boundaries, tasks the Tribunal expressly declined to undertake. Rather, its lasting significance lies in how it clarified the legal framework of UNCLOS itself: what maritime entitlements States may lawfully claim, what assertions the Convention displaces, and how States must exercise their rights and duties at sea.
How the Case Was Framed: Law, Not Sovereignty
The Philippines initiated arbitration in January 2013 against the backdrop of rising tensions in the South China Sea, particularly around Scarborough Shoal and other features in the Spratly Islands. China’s asserted “nine-dash line” overlapped extensively with maritime areas lying within 200 nautical miles of the Philippines’ coasts, areas where the Philippines claimed exclusive economic zone (EEZ) and continental shelf rights under UNCLOS.2
Critically, the Philippines did not ask the Tribunal to determine sovereignty over islands, rocks, or reefs, nor to delimit maritime boundaries. Instead, it asked the Tribunal to interpret and apply UNCLOS on specific legal questions, including:
- whether claims to “historic rights” within the nine-dash line were compatible with the Convention;
- the legal status of maritime features in the Spratly Islands and their capacity to generate maritime zones;
- whether China violated the Philippines’ sovereign rights within its EEZ;
- whether China breached its obligations to protect and preserve the marine environment; and
- whether China failed to act in good faith during the pendency of the proceedings.
This careful framing allowed the Tribunal to exercise jurisdiction while remaining within UNCLOS’s compulsory dispute-settlement framework.3
The Tribunal’s Core Legal Findings
1. The Nine-Dash Line and the Limits of “Historic Rights”
The Tribunal held that UNCLOS establishes a comprehensive allocation of maritime rights and entitlements. Where States have ratified the Convention, its provisions govern claims to maritime zones and resources.4
To the extent China asserted “historic rights” to living or non-living resources within the sea areas enclosed by the nine-dash line, beyond what UNCLOS permits, those claims were incompatible with the Convention and therefore without legal effect.5
The Tribunal did not rule on sovereignty over maritime features, nor did it deny the existence of historic fishing practices in general. Its finding was narrower and more precise: UNCLOS leaves no room for exclusive historic resource claims that cut into another State’s EEZ.
2. Feature Classification Determines Maritime Entitlements
Applying UNCLOS, the Tribunal assessed maritime features in their natural condition, unaffected by land reclamation or artificial modification.6 It found that Subi Reef, Mischief Reef, and Second Thomas Shoal were submerged at high tide and therefore incapable of generating any maritime zones of their own.
More broadly, the Tribunal concluded that none of the high-tide features in the Spratly Islands qualifies as an “island” capable of generating an exclusive economic zone or continental shelf under Article 121(3). It further held that the Spratly Islands cannot be treated as a collective unit for purposes of maritime entitlements.7
The legal consequence is clear and operationally significant: land reclamation cannot create maritime rights where the Convention withholds them.
3. Violations of the Philippines’ Sovereign Rights in the EEZ
Having identified the applicable maritime entitlements, without engaging in maritime boundary delimitation, the Tribunal found that certain contested areas fell within the Philippines’ EEZ. In those areas, it held that China violated the Philippines’ sovereign rights by interfering with fishing and petroleum exploration activities, constructing artificial islands and installations without consent, and failing to prevent its nationals from exploiting living marine resources.8
This finding gave concrete meaning to the concept of EEZ sovereign rights under UNCLOS Article 56, translating treaty language into enforceable legal standards.
4. Traditional Fishing Rights at Scarborough Shoal
The Tribunal recognized the existence of long-standing traditional fishing rights at Scarborough Shoal, grounded in artisanal fishing practices predating the modern law of the sea. While expressly declining to rule on sovereignty over the shoal, it held that China unlawfully interfered with those traditional fishing rights by restricting access beginning in May 2012. This aspect of the Award confirms that certain non-exclusive fishing rights may subsist independently of unresolved sovereignty claims where consistent historical usage is established.9
5. Environmental Harm and Due-Diligence Obligations
The Tribunal found that China’s large-scale dredging and reclamation activities caused severe harm to coral reef ecosystems, breaching UNCLOS obligations to protect and preserve the marine environment. It also held that China failed to exercise due diligence to prevent destructive fishing practices by its nationals.10
These findings confirmed that environmental obligations under UNCLOS Part XII are binding legal duties, not merely aspirational commitments.
6. Unlawful Aggravation of the Dispute
Finally, the Tribunal concluded that China’s conduct during the arbitration—particularly large-scale reclamation and construction—aggravated the dispute and was incompatible with a State’s obligations during compulsory dispute-settlement proceedings. It found that these actions caused irreversible harm to the marine environment and compromised evidence relevant to determining the natural condition of the features at issue.11
The Award’s Enduring Legal Meaning
Nearly a decade later, the South China Sea remains politically contested, but the 2016 Arbitral Award continues to serve as a clear legal reference point under the rules all coastal States accepted when they joined UNCLOS. Issued through the Convention’s dispute-settlement process and final as a matter of international law, the Award clarified three core points: sweeping historic claims cannot override the EEZ system, the legal status of maritime features determines what rights can be claimed from them, and States have enforceable duties to protect the marine environment.
For governments, naval commanders, and maritime operators, the message is straightforward. Lawful activity at sea depends on rights granted by the Convention—not on power, land reclamation, or lines drawn on maps. When States act outside those rules, the consequences are not only diplomatic; they carry legal, reputational, and operational costs that grow over time and limit future choices.
Footnotes:
- South China Sea Arbitration (Philippines v. China), Award, PCA Case No. 2013-19 (July 12, 2016) [hereinafter SCS Arbitration Award]. ↩︎
- United Nations Convention on the Law of the Sea, Annex VII, arts. 1–3, Dec. 10, 1982, 1833 U.N.T.S. 397 [hereinafter UNCLOS]. ↩︎
- UNCLOS arts. 286–288; UNCLOS, Annex VII, art. 9. ↩︎
- SCS Arbitration Award, supra note 1 ¶¶225–226, 261–262. ↩︎
- Id. ¶¶261–262. ↩︎
- UNCLOS, arts. 13, 121. ↩︎
- SCS Arbitration Award, ¶¶407–412 and 542–646. ↩︎
- SCS Arbitration Award, ¶¶225–226, 646–647, 716, 757. ↩︎
- Id. ¶¶ 804–814. ↩︎
- Id. ¶¶ 941–993. ↩︎
- UNCLOS, arts. 279–283; UNCLOS, Annex VII, art. 9; SCS Arbitration Award, ¶¶ 1169–1178. ↩︎