Under the U.N. Convention on the Law of the Sea, Can China Adversely Possess and Militarize Islands of the South China Sea?

Lauren Richards, Vol. 37 Associate Editor

China’s militarization of islands in the South China Sea threatens the right of innocent passage by States and, therefore, may pose a threat to international law.[1] The U.N. Convention on the Law of the Sea (UNCLOS) establishes a 200-mile continental shelf beyond the coastal State.[2] This entitles the coastal State to an additional 200 miles beyond the border of its territorial sea, which extends 12 miles from the coastal State.[3] In the territorial sea and continental shelf, all States have a right of continuous, expeditious, and innocent passage.[4] China claims a significant portion of the territory of the South China Sea as its own over the protestation of several other States in the region.[5] As a result of recent militarization of man-made islands in the South China Sea, China is potentially threatening the right of passage of these States, and others.

China’s claim to the islands could legally arise under territorial acquisition through prescription, a method similar to adverse possession in U.S. law.[6] China’s occupation and militarization of these man-made islands could effectively give it a right of sovereignty over the islands and, by extension, over the surrounding seas.[7] Politically, this presents issues with surrounding States in the South China Sea who also lay claim to this territory and the surrounding waters.[8] Legally, the issue arises if the right of innocent passage established in UNCLOS, and acknowledged more broadly in international law, is threatened.[9] China’s continued occupation of the islands strengthens its claims to the land and surrounding seas.

China’s militarization of the area and the potential threat this poses to passage of other States could be a violation of UNCLOS. International law allows for free passage up to 12 miles from the shore of a State.[10] If it is established that the holding of these islands is not valid under international law, then the United States may be allowed to sail within 12 miles and fly over the islands. If, however, China’s occupation of the islands is allowed, the U.S. military’s invasion of the 12-mile region surrounding the islands could be a violation of international law. Under Article 25 of UNCLOS, the coastal State (China) may take necessary measures to prevent passage within its territorial sea that it deems not innocent.[11]

In the event that China’s occupation and subsequent militarization of these islands is a violation of international territorial laws, there is an issue of enforcement of international law and of UNCLOS. UNCLOS is violated if the militarization presents a threat to innocent passage and international law is violated if the territorial claims infringe upon the territorial rights of another State.[12] Because the territorial claims have long been under political dispute, a slightly more answerable question is whether the United States can use military patrols to maintain the right of free passage near the islands. In addition, it should be evaluated whether the United States can use military patrols within the 12 miles of seas surrounding the islands and fly military aircraft through the islands’ airspace without authorization from China.

Assuming that peaceful resolution of this dispute through negotiations between the parties will be unachievable given the long history of territorial concerns, UNCLOS allows for the use of the International Tribunal for the Law of the Sea, the International Court of Justice, an arbitral tribunal, or a special arbitral tribunal.[13] UNCLOS makes clear that the signing nations have committed to a peaceful resolution.[14] Because this is a heavily contested area of international law, it is most likely necessary that a tribunal be used to evaluate the legality of the actions of both China and the United States. The use of a tribunal would be both practical and adhere to international law guidelines rather than resorting quickly to military threats. Because of the commitment by the Convention to a peaceful resolution, a respect for international law should be sought rather than a jump to military force.[15] UNCLOS clearly provides for a peaceful alternative with a neutral adjudicator under international law.[16] Perhaps the United States should adhere to this and defer to the guidelines set forth by UNCLOS rather than taking matters into its own hands and risking violating international law.

There are, of course, potential consequences to a lack of quick and efficient military intervention and allowing China to expand its power in the South China Sea. However, the implications of ignoring a peaceful commitment by the Convention and moving to military threats before an evaluation under international law is made could also be problematic. The United States risks involving itself in another international dispute when peaceful options are yet unexplored. In addition, it risks violating international law by invading China’s territorial waters in the event that international law decides China has a right to the man-made islands. Finally, the United States risks taking on a role of international peace keeper and the protector of navigation in the South China Sea. Deferring to a tribunal’s evaluation of the situation could avoid unnecessary involvement and criticism. In addition, it would show a clear effort to respect the methods of dispute resolution set forth by the countries involved in the Convention.


[1] Scott Neuman, U.S. Defense Secretary: Militarization of South China Sea Is Unacceptable, Nat’l Pub. Radio (May 29, 2015), http://www.npr.org/sections/thetwo-way/2015/05/29/410596015/eu-japan-express-concern-over-chinas-moves-in-south-china-sea.

[2] U.N. Convention on the Law of the Sea, Dec. 10, 1982, 1833 U.N.T.S. 397.

[3] Id.

[4] Id.

[5] Id.

[6] Surya Prakash Sharma, Territorial Acquisition, Disputes, and International Law 112 (1997).

[7] Id.

[8] Jeremy Page, Carol E. Lee & Gordon Lubold, China’s President Pledges No Militarization in Disputed Islands, Wall Street Journal (Sept. 25, 2015), http://www.wsj.com/articles/china-completes-runway-on-artificial-island-in-south-china-sea-1443184818.

[9] See U.N. Convention on the Law of the Sea, supra note 2.

[10] Id.

[11] Id.

[12] Id.

[13] Id.

[14] Id.

[15] Page, supra note 8.

[16] See U.N. Convention on the Law of the Sea, supra note 2.