The South China Sea dispute is a long-standing and ongoing maritime sovereignty dispute involving China, and its surrounding neighbours including Taiwan, Brunei, Malaysia, the Philippines, and Vietnam. There has been lots of hype in the media of late. The Sea is a focus of international confrontation due to overlapping claims within the region, its current and strategic importance as a key route for trade and commerce, and its extensive energy and fishing resources.

The Sea is semi-enclosed, approximately 648, 000 square miles extending from the Strait of Malacca to the Straight of Taiwan. 1 It comprises hundreds of small islands, reefs, and atolls, the most controversial of which is the Spratly Islands.1 Tensions over the region have existed since the Cold War however they have become more pronounced since the 1990s as a consequence of globalisation, surging economic growth in the region, military modernisation in China, enhanced demand for energy resources, expanding competition for maritime resources, and China’s status as a rising power and rival to the US.2

While the United Nations Convention on the Law of the Sea (UNCLOS) is recognised by civilised states to regulate maritime rights and obligations concerning the sea, China asserts it has a historical right (in the form of its nine-dashed line map from 1947) which overrides UNCLOS and provides a basis for a claim to approximately 70–75% of the South China Sea.3

This article explores the dispute by providing an overview of rights conferred under UNCLOS and distinguishing how they differ from China’s nine-dashed line. It also provides a brief history of the events which led to the South China Sea Arbitration case and discusses the case's significance including the Permanent Court of Arbitration’s Award and China and the international community’s resultant response.

United Nations Convention on Law of the Sea: The applicable international law

The United Nations Convention on Law of the Sea (UNCLOS) was adopted and signed in 1982 before being amended and enforced in 1994. It is an international treaty comprising 320 articles regulating navigational rights, territorial sea limits, economic jurisdiction, the legal status of resources on the seabed and beyond limits of national jurisdiction, the passage of ships through narrow straits, conservation, and management of living marine resources, protection of the marine environment, a marine research regime, and a binding procedure for settlement of disputes between States.

The Convention enables ad hoc arbitration under Annex VII of UNCLOS and special arbitral tribunal formation procedures for specific fields to settle specific kinds of disputes.4 It also established the International Tribunal for Law of the Sea, the International Seabed Authority, and the Commission on the Limits of the Continental Shelf to assist in its enforcement and implementation.5 UNCLOS replaced the four Geneva Conventions of April 1958 which had previously governed rights and activities of territorial sea and the contiguous zone, the continental shelf, the high seas, fishing, and conservation of living resources on the high seas.5 The treaty has been signed by all claimants in the South China Sea dispute and specifies clear laws on the waters bound by surrounding territories of nation-states.6 Under UNCLOS, all regulations are established from the baselines of sovereign states and inhabited islands as shown here on slide 5 7

A key issue with UNCLOS in the context of the South China Sea dispute is that the application of the law in the region is especially challenging.8 This is due to several islands, reefs, banks, and shoals with contestable status existing within the region and the fact that maritime laws are conferred from the baselines of sovereign states and inhabited islands and the status of specific features within the sea.8These issues make it complex to determine the rights to claims made by the Association of Southeast Asian Nations (ASEAN) countries surrounding the sea including Taiwan, Vietnam, Malaysia, the Philippines, Brunei, Indonesia, Singapore, and China. ­ As of 31 January 2020, UNCLOS had 168 state parties including all ASEAN member states and China.9

China’s nine-dashed line 12

Although UNCLOS is the applicable law that governs the sea since its adoption, China has asserted that it continues to possess a historic right to approximately 70–75% of the region as noted on its nine-dashed line map.10 It first did so in a letter to the UN Secretary-General stating that land and sea are areas that China has sovereign rights over.10 China’s legal claim is based on the notion of first discovery and its argument that the South China Sea was first mapped out by Chinese scholars as supported by archaeological evidence from several islands matching Han Dynasty era artifacts.11 If this argument were accepted, China believes it should mean it was the first claimant of the region and its rights thus predate those of the Philippines, Vietnam, Malaysia, and European colonisation.11 Additionally, it also maintains that its rights were not negated by the French colonisation of the Spratly and Paracel Islands.

Disputes in the South China Sea

China’s claim to its nine-dashed line has not been well received by other nations. 13 Consequently, since the early 1990s, nations involved in the dispute have commenced occupying islands, reefs, and other land features within the region to assert their perceived rightful claims.13China has also constructed a range of artificial islands and military bases within the region and has been using military force and operations to intimidate less powerful players in its pursuits.

Although territorial tensions commenced in the early 1970s, the region was relatively stable until February 1992 when Beijing passed its Territorial Waters Law.14 The Law was adopted at the Standing Committee of the National People’s Congress’ 24th meeting and stated China’s right to "exercise sovereignty over its territorial sea, incorporating offshore islands such as Taiwan, Diaoyu Island, Penghu Islands, Dongsha Islands, Nansha (Spratly) Island and other islands."14 After the law was passed, China’s People’s Liberation Army Navy (PLAN) was charged with responsibility for enhancing offshore defence and "building a survivable sea-based nuclear retaliation force."14

In 1995, China moved to occupy marine territory claimed by other ASEAN nations. The Philippines responded with strong diplomatic protests to China however, they went relatively unrecognised and had little impact on the situation.14 Other surrounding countries such as Malaysia and Singapore did not feel overly threatened by China’s conduct at that time and resultantly offered little support to the Philippines.14 In response, the Philippines Ramos Administration strengthened its Armed Forces via a $2 billion investment in its external defence, military hardware, and weapons for the Navy and Airforce.14 As tensions increased ASEAN stepped in and ultimately prompted discussions leading to the creation of a Code of Conduct by Foreign Ministers being developed for the region in 1996.14 The Declaration of the Code of Conduct of Parties in the South China Sea was signed on 4 November 200215; it stated that parties would respect the freedom of navigation in the South China Sea and resolve disputes without resorting to threats or use of force, however, it lacked dispute resolution guidance and mechanisms and did not prevent any parties from making new occupations in the region.16

The declaration did little to resolve the dispute. As ASEAN countries became more concerned with China’s assertions and enforcement of its nine-dashed line and non-compliance with UNCLOS, the Code of Conduct, and other bilateral agreements, it became clear to international institutions and the international community that the tensions had a significant capacity to escalate into something catastrophic.

The South China Sea Arbitration case

Relations in the South China Sea took a substantial downturn in 2009 when Vietnam and Malaysia (jointly) and Vietnam (individually) took action against China for areas of the continental shelf beyond 200 nautical miles, in 2011 when an incident occurred with the Philippines seismic survey ship and China’s maritime surveillance ships at Reed Bank and again in 2012 when a confrontation continued for months between Chinese and Philippine vessels at Scarborough Shoal.17

The Philippines was precluded from being able to exercise its rights under UNCLOS. Although it has made numerous pleas to China regarding its rightful sovereign claim to the area, China refused to remove its vessels from the areas in dispute and insisted it was acting appropriately given the area enclosed by the nine-dashed line. This placed the Philippines in a very difficult position whereby legal action was the only viable option available to resolve the dispute.18 While a complete and detailed review of all tensions within the region falls beyond the scope of this article, the key issue to recognise is that China’s conduct and retaliation from surrounding countries led to the US asserting its alliance with Vietnam and other ASEAN nations and contributed to significant instability in the region.18The events at Scarborough Shoal also ultimately led to the Philippines initiating the arbitration case against China by issuing a Notification and Statement of Claim following the dispute settlement provisions of UNCLOS under Article 287 and Annex VII.18 The case is known as the South China Sea Arbitration Case and is perhaps the most significant event that has occurred for determining rightful sovereign claims within the region.

China’s rejection of the Permanent Court of Arbitration’s Award for The South China Sea Arbitration case In its submissions of approximately 4000 pages to the Permanent Court of Arbitration (PCA), the Philippines contested China’s claims to its nine-dashed line map, sought clarity regarding its sovereign rights to its exclusive economic zone and continental shelf, and requested clarification regarding the status of submerged features and China’s unlawful activities in the region.19

China rejected the Philippines' claims and refused to participate in the arbitration on the basis that the claims fell outside the PCA’s jurisdiction and were unfounded under UNCLOS.20 Despite this, proceedings persisted after the PCA determined that the majority of claims did fall within its jurisdiction; an arbitrator was appointed on China’s behalf given its refusal to participate.20The Merits Hearing was conducted from 24–30 November 2014 and resulted in the PCA making an award that China’s nine-dashed line map has no legal basis and reinforcing the significance of UNCLOS and its applicability in the region.21 It also found that China had violated international law through its disregard for environmental obligations due to fishing activities, interference with vessels, and the construction of artificial islands. Additionally, the PCA also determined that China had impinged on the Philippines' rights to resources within the exclusive economic zone and continental shelf.22 While the decision was celebrated by the Philippines and ASEAN countries, China responded with anger, criticised the PCA, and publicly stated the ruling had no binding legal effect.22

Does a peaceful resolution seem likely after the South China Sea Arbitration Case?

Given China’s response to the arbitration case, the international community continues to have substantial concerns about the South China Sea and there is ongoing debate regarding whether the persisting dispute can be resolved peacefully. China’s economy is growing rapidly and it is well known that its demand for energy and marine resources is steadily increasing. An even more significant issue of global concern is that the United Nations Conference on Trade and Development (UNCTAD) estimates that approximately “80 percent of global trade by volume and 70 percent by value is transported by sea…with the South China Sea carrying an estimated one-third of global shipping.” 23 In context, that translates to an estimated $5.3 trillion worth of goods traveling through the South China Sea annually.23If China continues to ignore the PCA Award and attempts to enforce its nine-dashed line by building structures and using military force within the Sea, it could be very problematic for ships traversing the region and potentially damage the global economy.

At present, policymakers and scholars are highlighting that resolution through aggressive means would likely be damaging to China more so than any other nation. While some nations have resorted to undertaking freedom of navigation exercises in the South China Sea to reinforce the findings of the arbitration case, most are taking a more diplomatic approach and doing what they can to prevent conflict and tensions from escalating.24

The reality is that China would likely face the wrath of international legal institutions, the US military, and most ASEAN countries if a serious dispute occurred and it is thus in its own best interest to abide by UNCLOS and cease undermining the sovereign rights of Southeast Asian coastal states.25 Australia has highlighted its intent to avoid freedom of navigation exercises but cooperate with the US in any other peaceful attempts to resolve the dispute.25 It has also committed to stepping up coordination with Southeast Asian littoral states with a view to putting the dispute on the Quad leaders’ agenda.25

The Philippine Strategic Forum has also recommended 1) the dispute be set aside temporarily to prevent it from escalating further and emphasis be placed upon strengthening relations with other ASEAN counties, 2) that military action should be avoided and restraint to be exercised in using armed forces (including those of the US) and 3) that all nations should seek to follow basic principles of international law such as using non-violent dispute resolution concerning unsettled issues of territorial ownership and delimiting overlapping maritime boundaries.26 Although tensions in the region still exist, it seems highly likely that China will be forced to submit to the PCA ruling as the consequence of not doing so would likely be to its detriment.

The South China Sea dispute is a complex and significant issue concerning most nations globally. The arbitration case has been useful in highlighting that China’s territorial claims based on historic and archaeological factors are overridden by the UNCLOS and that the provisions of UNCLOS ought to be adhered to within the South China Sea region. Although China has publicly rejected the PCA’s Award, it is likely to succumb to pressures from the international community to behave in a manner that protects global interests. The key factor underpinning this is that China itself would likely suffer tremendously if significant unrest occurred in the region. While China has a strong military and is a rising power, its internal economy would be greatly affected if the US and most ASEAN countries retaliated in response to its conduct. The reality is that the dispute is likely to persist with resolution occurring per basic principles of international law. China would do itself a great disservice by causing further tension in the region given that it is trying to enhance its economy and continue striving to become a global player.


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2 Southgate L Interests, Balancing and the Role of the Vanguard State, Chapter 5 Bristol University Press 2019.
3 Reichler P A discussion on the Philippines’ South China Sea Arbitration Case Centre for Strategic & International Studies 4 December 2013.
4 Spangler J and Lui F South China Sea Lawfare: Legal Perspectives and International Responses to the Philippines v China Arbitration Case South China Sea Think Tank/ Taiwan Center for Security Studies, January 29, 2016.
5 International Union for Conservation of Nature (IUCN) UNCLOS 2020.
6 Poling, Gregory B. 2013. The South China Sea in Focus: Clarifying the Limits of Maritime Dispute. Center for Strategic and International Studies (CSIS). New York: Rowman & Littlefield.
7 Schofield C Baselines Issues in the South China Sea: Challenges in Defining the ‘Boundary’ between Land and Sea University of Wollongong Faculty of Law 2013.
8 Black B The South China Sea Disputes a Clash of International Law and Historical Claims Pennsylvania State University March 2018.
9Centre for International Law (CIL) The United Nations Convention on Law of the Sea (UNCLOS) July 2020.
10 Reichler P A discussion on the Philippines’ South China Sea Arbitration Case Centre for Strategic & International Studies 4 December 2013.
11 Campell C & Salidjanova N South China Sea Arbitration Ruling: What Happened and What’s Next U.S — China Economic and Security Review Commission Issue Brief 12 July 2016.
12 Nguyen Dang T China’s Nine Dotted Lines in the South China Sea: The 2011 Exchange of Diplomatic Noted Between the Philippines and China Ocean Development & International Law 43:35–56, 2012 Routledge Taylor and Francis 2012.
13 Junyuan P & Jing S A Critical Assessment of China’s Role in the South China Sea Dispute Journal of Politics and Law Vol. 13 №4 October 2020.
14 Southgate L Interests, Balancing and the Role of the Vanguard State, Chapter 5 Bristol University Press 2019.
15 ASEAN Declaration on Conduct of Parties in the South China Sea 17 October 2012.
16 Southgate L Interests, Balancing and the Role of the Vanguard State, Chapter 5 Bristol University Press 2019.
17 Batongbacal J Arbitration 101: Philippines v China Asia Maritime Transparency Initiative 21 January 2015.
18 Reichler P A discussion on the Phillippines’ South China Sea Arbitration Case Centre for Strategic & International Studies 4 December 2013.
19 Spangler J and Lui F South China Sea Lawfare: Legal Perspectives and International Responses to the Philippines v China Arbitration Case South China Sea Think Tank/ Taiwan Center for Security Studies, January 29, 2016.
20 Permanent Court of Arbitration The South China Sea Arbitration (The Republic of Philippines v The People’s Republic of China) Case Information.
21 Spangler J and Lui F South China Sea Lawfare: Legal Perspectives and International Responses to the Philippines v China Arbitration Case South China Sea.
22 Think Tank/ Taiwan Center for Security Studies, January 29, 2016. China Power Team How Much Trade Transits the South China Sea? China Power 2 August 2017/ Updated 25 January 2021.
23 Rosen M After the South China Sea Arbitration; Where do we go after the panel has spoken? The Diplomat 21 June 2016.
24 Pompeo M U.S Position on Maritime Claims in the South China Sea U.S. Embassy in Cambodia 13 July 2020.
25 Cook M Australia’s South China Sea Challenges Lowy Institute Policy Brief 26 May 2021.
26 Ibarra EJ Toward Peaceful Settlement of the South China Sea Disputes Philippine Strategic Forum 2 December 2020.