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Limits in the Seas Executive Summary
January 14, 2022

United States Department of State 
Bureau of Oceans and International Environmental and Scientific Affairs

Limits in the Seas
No. 150

People’s Republic of China: Maritime Claims in the South China Sea
[Full Report in PDF format] 

Executive Summary 

This study examines the maritime claims of the People’s Republic of China (PRC) in the South China Sea.  The PRC’s expansive maritime claims in the South China Sea are inconsistent with international law as reflected in the 1982 United Nations Convention on the Law of the Sea (“Convention”). 

The PRC asserts four categories of maritime claims* in the South China Sea: 

  • Sovereignty claims over maritime features.  The PRC claims “sovereignty” over more than one hundred features in the South China Sea that are submerged below the sea surface at high tide and are beyond the lawful limits of any State’s territorial sea.  Such claims are inconsistent with international law, under which such features are not subject to a lawful sovereignty claim or capable of generating maritime zones such as a territorial sea. 
  • Straight baselines.  The PRC has either drawn, or asserts the right to draw, “straight baselines” that enclose the islands, waters, and submerged features within vast areas of ocean space in the South China Sea.  None of the four “island groups” claimed by the PRC in the South China Sea (“Dongsha Qundao,” “Xisha Qundao,” “Zhongsha Qundao,” and “Nansha Qundao”) meet the geographic criteria for using straight baselines under the Convention.  Additionally, there is no separate body of customary international law that supports the PRC position that it may enclose entire island groups within straight baselines. 
  • Maritime zones.  The PRC asserts claims to internal waters, a territorial sea, an exclusive economic zone, and a continental shelf that are based on treating each claimed South China Sea island group “as a whole.”  This is not permitted by international law.  The seaward extent of maritime zones must be measured from lawfully established baselines, which are normally the low-water line along the coast.  Within its claimed maritime zones, the PRC also makes numerous jurisdictional claims that are inconsistent with international law. 
  • Historic rights.  The PRC asserts that it has “historic rights” in the South China Sea. This claim has no legal basis and is asserted by the PRC without specificity as to the nature or geographic extent of the “historic rights” claimed. 

The overall effect of these maritime claims is that the PRC unlawfully claims sovereignty or some form of exclusive jurisdiction over most of the South China Sea.  These claims gravely undermine the rule of law in the oceans and numerous universally-recognized provisions of international law reflected in the Convention.  For this reason, the United States and numerous other States have rejected these claims in favor of the rules-based international maritime order within the South China Sea and worldwide. 

* Islands in the South China Sea over which the PRC claims sovereignty are also claimed by other States.  This study examines only the maritime claims asserted by the PRC and does not examine the merits of sovereignty claims to islands in the South China Sea asserted by the PRC or other States.  The United States takes no position as to which country has sovereignty over the islands in the South China Sea, which is not a matter governed by the law of the sea. 

References to the Philippines 

In 2016, having considered the PRC’s dashed-line claim, an arbitral tribunal convened in accordance with the Convention reached a similar conclusion in The South China Sea Arbitration (The Republic of the Philippines v. The People’s Republic of China).  The arbitral tribunal issued a unanimous decision, which is final and binding on the Philippines and the PRC, finding that: China’s claims to historic rights, or other sovereign rights or jurisdiction, with respect to the maritime areas of the South China Sea encompassed by the relevant part of the “nine-dash line” are contrary to the Convention and without lawful effect to the extent that they exceed the geographic and substantive limits of China’s maritime entitlements under the Convention [and that] the Convention superseded any historic rights, or other sovereign rights or jurisdiction in excess of the limits imposed therein.  

The PRC claims sovereignty over all of the South China Sea islands (and numerous other maritime features, as discussed below).  Each island or group of islands is claimed by at least one other claimant: Philippines (Scarborough Reef and some of the Spratly Islands), Malaysia (some of the Spratly Islands), Brunei (Louisa Reef, within the Spratly Islands), Vietnam (Spratly Islands and Paracel Islands), and Taiwan (all islands and island groups).  The geographic features described above are located within the dashed lines that have appeared in various locations on some PRC maps since being published by the Nationalist government of the Republic of China in 1947. 

Numerous States, including Australia, Japan, New Zealand, the Philippines, Vietnam, the United Kingdom, and the United States have protested the PRC’s baselines around the Paracel Islands as inconsistent with international law as reflected in the Convention. 

Although the PRC has not officially promulgated straight baselines around the areas it describes as Nansha Qundao, its statements asserting the right to draw such baselines have led to opposition by numerous States, including Australia, France, Germany, Japan, New Zealand, the Philippines, the United Kingdom, the United States, and Vietnam.  Considering that very few States publicly protest excessive maritime claims, these protests by a relatively large number of States are a particularly forceful rejection of the PRC’s legal position.  

The tribunal’s award is final and binding on the PRC and the Philippines pursuant to Article 296 of the Convention. 

The international community, including littoral States of the South China Sea, has made clear that it rejects the PRC’s historic rights claim. Australia, France, Germany, Indonesia, Japan, Malaysia, New Zealand, the Philippines the United Kingdom, the United States, and Vietnam have all publicly objected to the PRC’s historic rights claim, which is inconsistent with international law.  The tribunal in The South China Sea Arbitration also rejected the PRC’s claims to historic rights in the South China Sea.   

Click here to read the Filipino version of the Executive Summary