Still Legally Relevant: The South China Sea Award After Ten Years

A decade after the issuance of the 2016 South China Sea Arbitration Award, tensions in the South China Sea (SCS) have intensified. There has been a growth in the number of incidents and in the degree of force that China and the Philippines have employed at sea. Moreover, that China continues to reject the Award as “null and void” has arguably undermined the Award’s authority and legitimacy. These situations raise questions about the effectiveness of the Award.

Notwithstanding this, there are subtle yet meaningful developments suggesting that the Award remains alive, legally relevant and continues to shape state conduct in the SCS. Since 2016, China has shown a greater tendency to frame and consolidate its maritime claims through the technical vocabulary of the law of the sea. This is reflected in a clear shift in how China draws baselines for its claimed groups of offshore maritime features (GOMFs). At the same time, Southeast Asian claimant states, particularly Malaysia, the Philippines and Vietnam, have persistently advanced their maritime claims on the basis of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) and directly or indirectly on the legal reasoning of the Award, which confirms the significance of the 2016 judgment in legal practices in the SCS.

Under the law of the sea, a “baseline” is the first line at sea from which coastal States claim their maritime zones. UNCLOS allows three types of baselines: continental States (like China) can adopt normal baselines along the low-water line of the coast or straight baselines for coastlines that are deeply indented or cut into; only archipelagic States (like Indonesia) may draw archipelagic baselines linking the outermost points of their islands.

China is a continental State that claims sovereignty over several GOMFs in the East and South China Seas. It established straight baseline systems for the Paracel Islands in the SCS in 1996 and the Diaoyu Dao/Senkaku Islands in 2012. Although China has not formally characterised these as ‘archipelagic baselines’ (Editor’s Note: Under UNCLOS, this is something China cannot do, since it is not an archipelagic state), their configuration, such as connecting offshore features into a single unit, closely resembles that of an archipelagic baseline system. This practice was considered inconsistent with Article 47 of UNCLOS, which was reaffirmed in the 2016 Award.

In 2024, China announced a new baseline system for Scarborough Shoal, a feature it regards as part of the Zhongsha Island group. Despite continuing to assert that Zhongsha constitutes a single unit, China drew baselines only around Scarborough Shoal, departing from its earlier practice, where it might have established a system linking Scarborough Shoal with other features in the Zhongsha group. Instead, by drawing baselines solely around this feature, China treated it as an individual maritime feature.

This development suggests a subtle yet significant shift in China’s law of the sea practice. It now appears that China is focusing on strengthening its maritime claims in the SCS through so-called straight baselines surrounding GOMFs, instead of ostensible archipelagic baselines. Importantly, this practice reflects China’s inconsistent application of baseline rules for GOMFs, further reinforcing the 2016 Tribunal’s finding that there was no customary international law on drawing baselines outside of the UNCLOS framework.

With respect to the SCS claimant states in ASEAN, there are certain developments in state practices suggesting the impact of the 2016 Award, especially on their position that maritime features in both the southern part and the northern part of the SCS are incapable of generating any maritime entitlement beyond a 12-nautical-mile territorial sea.

First, the Philippines’ position concerning maritime features in the southern SCS has shifted to align with the 2016 Award. Prior to the Award, the Philippines had protested Vietnam’s submission and the joint submission of Malaysia and Vietnam to the Commission on the Limits of the Continental Shelf (CLCS) concerning the extension of their continental shelves in the southern part of the SCS. The Philippines argued that, among other reasons, the claimed extended continental shelves overlapped with areas also considered subject to its entitlement. This appeared to imply that certain features in the Spratly Islands and Scarborough Shoal could constitute “high-tide features” capable of generating a continental shelf under UNCLOS. However, in its communication of 6 March 2020, the Philippines shifted its language from referring to “overlapping” maritime zones to merely noting that the submissions “cover[ed] features” over which it claimed sovereignty, a shift made clearer when the Philippines made its first submission for an extended continental shelf in the SCS after the Award.

Second, the practices of Malaysia and Vietnam after the Award may reflect its impact: both countries submitted further claims concerning extended continental shelves in the northern and central parts of the SCS in 2019 and 2024, respectively. From these submissions, it can be inferred that for both countries, none of the features in the Paracel Islands can generate a continental shelf. Malaysia’s submission does not consider the possibility of overlapping maritime entitlements being generated from features in the Paracel Islands. Vietnam, despite maintaining sovereignty claims over the Paracel Islands, does not assert an extended continental shelf generated from those features in its submission. These practices may suggest that both States have relied on the reasoning of the 2016 Award concerning the legal status of maritime features in the southern SCS to apply a similar approach to the northern SCS.

A decade has passed since the SCS Award was issued. The tensions at sea in the region should not overshadow the subtle legal practices of regional countries, nor should the Award’s effectiveness be assessed solely by visible conduct at sea, but by the evolving legal positions of the parties to the disputes. Their legal practices carry greater long-term weight in shaping the normative order of the South China Sea.

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