Artificial Islands and Low-Tide Elevations: The South China Sea Award Ten Years On

Re-examining the 2016 South China Sea Arbitral Award: why engineering sand onto submerged reefs cannot generate territorial sea or exclusive economic zones under UNCLOS Article 121.

THE HAGUE — A decade after the Permanent Court of Arbitration issued its landmark ruling in the South China Sea Arbitration (The Philippines v. China), the tribunal’s findings on the legal status of maritime features remain the cornerstone of contested freedom-of-navigation operations.

The core legal question continues to govern disputes over artificial installations: Can massive engineering works transform a submerged reef into a legal island capable of generating maritime zones?


1. The Tripartite Categorization Under UNCLOS

UNCLOS establishes a strict maritime hierarchy based entirely on a feature’s natural status at high tide:

High Tide Line ─────────────────────────────────────── ▲ │ Naturally above water ▼ ┌────────────────────────────────────────────────────────┐ │ Article 121(1): ISLAND │ │ Generates 12nm Territorial Sea + Contiguous Zone │ └────────────────────────────┬───────────────────────────┘ │ ┌───────────────────────┴───────────────────────┐ ▼ ▼ Article 121(3) ROCK FULL ISLAND STATUS

If a feature is submerged at high tide, it constitutes either:


2. The Legal Futility of Sand-Dredging: Article 60(8)

The 2016 Arbitral Award established the binding principle that a feature’s legal status is determined by its natural capacity prior to human intervention.

Dredging millions of tons of sand and pouring concrete to construct runways, deep-water ports, or military barracks on top of a low-tide elevation does not convert it into an island:


3. Systemic Implications

The Arbitral Tribunal’s rigorous objective standard prevents coastal states from weaponizing civil engineering to privatize international sea lanes. As naval powers continue to conduct Freedom of Navigation Operations (FONOPs) within 12 nautical miles of converted reefs, the 2016 ruling remains the bedrock legal shield against the unilateral enclosure of the global commons.