A captain of a dive boat secures the anchor

A captain of a dive boat secures the anchor while waiting off Koh Tao island in the Gulf of Thailand. (Photo: Romeo GACAD / AFP)

Why UNCLOS Matters

UNCLOS and Thailand: Security, Prosperity and Sustainability


Despite being a party to UNCLOS only in 2011, the Convention has served Thailand well. But UNCLOS should be updated in light of emerging maritime issues such as climate change.

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.

The United Nations Convention on the Law of the Sea (UNCLOS) has played a significant role in shaping the security, prosperity and sustainability of maritime Thailand. However, circumstances have arisen during the past 40 years. This means that UNCLOS needs to evolve in order to provide security for Thailand and the global maritime community.

Thailand is a maritime nation located between the Pacific Ocean to the east and the Indian Ocean to the west. With a maritime area of approximately 323,488 square kilometres (sq km) and valuable maritime industries, the seas and oceans are both a home and a source of sustenance for Thailand.

It is thus no surprise that Thailand has played a key part in the development of UNCLOS. At the 1958 UNCLOS I in Geneva, Major-General Prince Naradhip Bongsprabandh, the Minister of Foreign Affairs of Thailand, was appointed chair of the conference.

UNCLOS was adopted in 1982, but Thailand delayed ratification of UNCLOS for nearly three more decades until the kingdom ratified the Convention in 2011. One of the main reasons was the concept of an archipelagic State and Exclusive Economic Zones (EEZ). This greatly disadvantaged Thailand as a country that borders on semi-enclosed seas. This led Thailand to become a zone-locked State with no direct access to the high seas except through the EEZs of neighbouring State zones. As such, Thai fishermen were not able to access large areas of Thai historical fishing grounds. UNCLOS’ definition of EEZs — a maritime area extending 200 nautical miles from the shores of a coastal State — brought approximately 300,000 sq km of former Thai fishing grounds within the national jurisdiction of Thailand’s neighbouring States such as Malaysia and Indonesia. This also affected the freedom of navigation of Thai warships and limited the mobility of its naval forces.

Map of Thailand's EEZ

Thailand had a change of heart in the end. In keeping with the ASEAN spirit, the increasing need to utilise the oceans for economic benefit and address maritime security issues, Thailand decided to endorse the concept of an archipelagic State and recognise the EEZ concept. It became a Party to the Convention on 14 June 2011.

Thailand’s National Maritime Security Plan (2015-2021) was issued to develop and utilise all national powers — political, economic, military, social, psychological, or scientific — to uphold the kingdom’s national interests at sea. The plan sought to provide security, prosperity and sustainability. In 2019, the Thai Maritime Enforcement Command Centre was established to protect Thai national maritime interests in areas such as maritime law enforcement and maritime search and rescue.

UNCLOS has also provided a mix of successes and challenges for Thailand, such as settling maritime disputes, monitoring Illegal, Unreported and Unregulated (IUU) fishing and non-traditional threats, and providing marine environmental protection.

But UNCLOS has also given rise to maritime disputes between Thailand and Cambodia, Malaysia, and Vietnam. The Gulf of Thailand is a semi-enclosed sea. In 1979, Thailand concluded the Memorandum of a Joint Development Area with Malaysia, considered a prime example of bilateral cooperation in sharing a maritime border for mutual benefit. It has also settled the issue of overlapping maritime zones with Vietnam. The remaining overlapping claim area falls under a 2001 memorandum of understanding between Thailand and Cambodia, which serves as a platform for negotiation. However, there has been limited progress on the talks, as political and security stakes have impeded the resolution of boundary disputes. This year, both countries are preparing to restart the talks, using Thailand’s 1979 Memorandum of Joint Development Area with Malaysia as a model.

Another Thai achievement from UNCLOS concerns IUU fishing. In 2015, the European Union issued Thailand a yellow card, prompting the kingdom to reform its fishing industry to align with international standards. As a result of implementing measures under UNCLOS and the United Nations’ 1995 Fish Stock Agreement, Thailand has been able to shed the yellow card warning

The right of navigation and international protection of Thai fishing vessels are also ongoing concerns for Thailand. While some countries such as Malaysia and Indonesia have adopted their domestic laws imposing requirements on fishing vessels passing through their maritime zones, Thailand has some objections about the enforcement of such legislation as they are not in compliance with Articles 61 and 62 of UNCLOS. Malaysia, for example, had implemented legislation which calls for foreign fishing vessels to notify Malaysian authorities prior to transiting Malaysian waters. In 2009, Thailand issued a notification against states restricting foreign fisheries vessels from enjoying UNCLOS rights to innocent passage and freedom of navigation in their EEZs.

However, the emergence of new issues means UNCLOS may no longer be adequate. There are myriad maritime issues, such as maritime environmental incidents, climate change, rising sea levels, land reclamation, maritime autonomous vehicles, and the conservation of the biodiversity of areas beyond national jurisdiction (BBNJ).

UNCLOS is still considered infinitely valuable to humanity in regulating and conserving maritime resources. For Thailand, UNCLOS has been indispensable in the management of its internal affairs to attain the goals of security, prosperity and sustainability. The Convention encourages cooperation with other countries, and thus contributes to peace and security in the region. Nevertheless, there is room for UNCLOS to be updated to address rapidly evolving new challenges.


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.

Rear Admiral Somjade Kongrawd (retired, Royal Thai Navy) is a subcommittee member on Maritime Transportation and Merchant Marine in the Thai Senate.