Philippine coast guard personnel aboard Gabriela Silang

Philippine coast guard personnel aboard Gabriela Silang salute during a passing honour ceremony at the conclusion of a joint search and rescue exercise between the Philippine and US coast guards in the vicinity of the South China sea off Zambales on September 3, 2022. (Photo: TED ALJIBE / AFP)

Why UNCLOS Matters

UNCLOS: The Polestar for Philippine Maritime Ambitions


The United Nations Convention on the Law of the Sea has served the Philippines well in achieving its security, economic and environmental goals. The most high-profile application of UNCLOS was the country’s arbitration proceedings against China in 2013 over the South China Sea.

Editor’s Note:

This article is part of “UNCLOS 40th Anniversary Series – Why UNCLOS Matters” conceptualised by the Blue Security programme. The series, which commemorates the 40th anniversary of the UN Convention on the Law of the Sea, brings together established and emerging maritime security scholars from Southeast Asia and the broader Indo-Pacific to address the pertinence and relevance of UNCLOS. Blue Security brings together Australian and Southeast Asian experts to look at a range of maritime security issues across the region. The series was developed by Dr. Troy Lee-Brown and Dr. Bec Strating.

This year marks the 40th anniversary of the adoption of the United Nations Convention on the Law of the Sea (UNCLOS), undeniably the most important legally-binding instrument to apply to the world’s oceans. For the Philippines, this presents a timely opportunity to reflect on the role of UNCLOS in helping to achieve the country’s security, economic, and environmental goals.

The Philippines is an archipelagic state comprised of 7,641 islands. It has an approximate land area of around 300,000 square kilometres (sq km), while its maritime territories are estimated to be around 2,000,000 sq km. The Philippines is surrounded in all directions by bodies of water, including the Pacific Ocean to the east, the South China Sea to the west, the Bashi Channel to the north, and the Sulu and Celebes Seas to the south. It thus comes as no surprise that the Philippines identifies as a maritime nation.

This was the mindset that the Philippines brought to the UNCLOS negotiation process, where it championed the international recognition of the archipelagic doctrine — an important concept that unites land, water, and people into a single legal entity. The inclusion of the archipelagic doctrine into UNCLOS has had legal ripple effects that are still felt in the Philippines to this day. The concept is enshrined in the 1987 Constitution and is the basis for identifying the scope of the Philippine national territory. In 2009, the Philippines enacted a law that formally drew its archipelagic baselines to be in full conformity with the UNCLOS. In doing so, the country can now clearly reckon the length and breadth of various maritime zones under the convention. This move paved the way for bilateral negotiations with Indonesia for the delimitation of their overlapping exclusive economic zones (EEZs). It allowed the Philippines to formally claim an extended continental shelf in the Benham Rise region along its northeastern seaboard. The Philippines is also currently studying the possibility of designating archipelagic sea lanes (ASLs) in its archipelagic waters, a strategic move that can potentially help manage numerous concerns, including the entry of foreign military vessels and the impact of vessel traffic on vulnerable marine ecosystems.

Beyond the archipelagic doctrine, UNCLOS, as the “constitution of the oceans”, has been relevant to the Philippines in other issues as well. The most high profile of these has been the South China Sea dispute.

In 2013, the Philippines initiated arbitration proceedings against China under Annex VII of UNCLOS. The Philippine position was straightforward: it sought to safeguard its maritime rights and entitlements under UNCLOS, including through the invalidation of China’s so-called “Nine-Dashed-Line” claim on the ground that it has no basis under the convention. On 12 July 2016, the arbitral tribunal issued an award that handed the Philippines a sweeping victory in practically every important legal aspect of the case. Although the Philippines can objectively be considered the winner of the arbitration, the win is largely Pyrrhic. This is due to the fact that China refuses to recognise the arbitration proceedings and their outcome. This problem is compounded by the total absence of any enforceable mechanism in UNCLOS that can deal with a country’s non-compliance with judgments and awards (this also applies in general to any state-to-state dispute settlement under international law). This is a particularly distressing reality for weaker States taking on stronger States. In this sense, UNCLOS fails in its promise of establishing an effective dispute settlement system essential to maintaining the delicate balance of rights and obligations in the convention.

Although the Philippines can objectively be considered the winner of the arbitration, the win is largely Pyrrhic. This is due to the fact that China refuses to recognise the arbitration proceedings and their outcome. This problem is compounded by the total absence of any enforceable mechanism in UNCLOS that can deal with a country’s non-compliance with judgments and awards

Apart from the actual arbitration, the South China Sea dispute also has other dimensions which are directly related to the living and non-living resources in the area.

In 2018, the Duterte administration considered the possibility of entering into a joint development agreement with China in order to explore and exploit the potentially vast oil and gas reserves in the disputed area. It even went so far as to enter into a Memorandum of Understanding for the purpose of negotiating “on an accelerated basis, arrangements to facilitate oil and gas exploration and exploitation in relevant maritime areas consistent with applicable rules of international law.” Although the MOU references the UNCLOS (presumably an oblique way of saying that the MOU will operate within the legal framework of the Convention), it notably did not mention the arbitral award.

Negotiations did not progress and were eventually terminated in June 2022. This was likely due to two factors. There were unresolved constitutional and legal challenges to a joint development agreement. Second, China had engaged in progressively aggressive acts of harassment against the survey vessels of service contractors authorised by the Philippine government to conduct exploration activities in the country’s EEZ. As a result of the latter, the Philippine government suspended all exploration activities in the area. The new Marcos administration is reportedly considering the resumption of bilateral negotiations pursuant to the MOU.

In 2021, the Philippines decided to resume joint marine scientific research exploration (JOMSRE) with Vietnam in the South China Sea, consistent with the spirit of Article 123 of UNCLOS which encourages cooperation among States bordering semi-enclosed seas. The two countries had previously engaged in JOMSRE from 1994 to 2007. The earlier initiative resulted in generating important information concerning the state of coral reefs and fish stocks in the area. The resumed JOMSRE is intended to update that information as well as build closer cooperation and coordination between the two countries outside of, yet alongside, their respective territorial claims in the SCS.

Beyond the South China Sea dispute, the Philippines faces other ocean-related challenges that impact the country’s economy, food security, and environment. In all these cases, UNCLOS serves as the anchor for the country’s legal positions and the polestar for its maritime initiatives and ambitions. 


This article is part of the ‘Blue Security’ project led by La Trobe Asia, University of Western Australia Defence and Security Institute, Griffith Asia Institute, UNSW Canberra and the Asia-Pacific Development, Diplomacy and Defence Dialogue (AP4D). Views expressed are solely of its author/s and not representative of the Maritime Exchange, the Australian Government, or any collaboration partner country government.

Jacqueline F. Espenilla is the Director of The University of the Philippines’ Institute for Maritime Affairs and Law of the Sea, and Assistant Professor at The University of the Philippines College of Law.