Ambassador Pou Sothirak of the Cambodian Center for Regional Studies and ITLOS judge Horinouchi Hidehisa address a March 18 public lecture on the UNCLOS treaty. Hong Raksmey
Cambodia’s potential membership of the UN Convention on the Law of the Sea (UNCLOS) holds significant promise for strengthening the country’s maritime rights and sovereignty.
As Cambodia faces ongoing maritime disputes, particularly with Thailand over the Koh Kut area, the UNCLOS could serve as an invaluable legal framework for resolving tensions and securing the Kingdom’s maritime interests.
The UNCLOS, a comprehensive legal instrument that governs maritime disputes, territorial waters and the exclusive economic zones (EEZs) of coastal states, provides clear rights and obligations for member countries.
Adopted in 1982 and entering into force in 1994, it is an international treaty that establishes the legal framework for the use and conservation of the world's oceans and maritime resources.
UNCLOS is widely accepted as the “constitution of the oceans”, with over 160 countries as parties. However, some nations, including the US, have signed but not ratified the treaty.
In a public lecture on evolving UNCLOS towards maritime cooperation held at Raffles Hotel Le Royal Phnom Penh on March 18, Horinouchi Hidehisa, Judge of the International Tribunal for the Law of the Sea (ITLOS) and former ambassador of Japan to Cambodia, emphasised the importance of the convention for countries facing maritime disputes.
The disputed island of Koh Kut is closer to the Cambodian mainland than that of Thailand. Google
“Cambodia is currently taking the position that much of the convention is customary international law, so it does not necessarily need to ratify it to benefit from it,” said Horinouchi.
“However, becoming a member would offer clearer, definitive rights and obligations regarding Cambodia’s EEZ,” he added.
He explained that, like the US, which is not a member but still applies many aspects of the UNCLOS as customary international law, Cambodia could benefit from clearer legal standing in maritime issues with neighbouring countries, especially those that are already members of the convention.
As Cambodia continues to engage with Thailand over the Koh Kut issue, the convention would offer a structured path toward diplomatic resolution.
The legal framework provided by UNCLOS would give Cambodia the necessary tools to address territorial disputes based on international standards, strengthening its ability to protect its maritime interests.
In addition to resolving territorial claims, Cambodia’s 400-kilometre coastline and rich maritime biodiversity further underscore the potential benefits of UNCLOS membership.
Ambassador Pou Sothirak, distinguished senior advisor at the Cambodian Center for Regional Studies, highlighted that the Kingdom’s marine resources, including unique fish species and potential carbon deposits beneath the seabed, could be safeguarded through the legal protections offered by UNCLOS.
“UNCLOS is like an insurance company, you decide to take this matter to UNCLOS, you can be sure that Cambodia will be best protected, legally speaking,” he remarked.
“The law will judge based on evidence and proof, ensuring that Cambodia’s maritime resources, including fisheries and potential underwater carbon deposits, remain under its rightful control,” he added.
The potential to extend Cambodia’s maritime boundaries up to 200 nautical miles (about 370 kilometres) from a country’s coastline could provide the country with significant access to oceanic resources, making membership of UNCLOS even more crucial.
The international legal protections would also safeguard Cambodia’s biodiversity, with the possibility of discovering species that exist solely in its waters.
The benefits of membership extend beyond simply resolving territorial disputes.
The convention offers a framework for Cambodia to protect its sovereignty, access vital resources and ensure the sustainable management of its marine environment.
Horinouchi explained the process of becoming an UNCLOS member, noting that it can be done through ratification and through accession.
He added that is important for Cambodia to complete the necessary domestic legal work and establish laws that define the EEZ.
“A domestic legal process is required, so this is a lot of work for the parliament and also the relevant ministries,” said Horinouchi.
“But once this is done, Cambodia's position will be much stronger,” he added.
Horinouchi noted that after the National Assembly of Cambodia ratify the convention, it may be as little as 30 days before the UN may admit the Kingdom.
Ermenegildo Kupa Lopes, Timor-Leste ambassador to Cambodia, shared insights into his country’s successful resolution of its long-standing maritime boundary dispute with Australia, offering a potential model for Cambodia in future maritime issues.
Lopes highlighted the significance of the convention’s compulsory conciliation process, which played a pivotal role in resolving the Timor-Leste-Australia dispute over the Timor Sea’s oil and gas resources.
The process led to the signing of a treaty in 2018, which was officially ratified in 2019 with the support of the UN secretary-general.
“This was the first-time compulsory conciliation was used between Timor-Leste and Australia, and it was a success,” Lopes stated.
“Timor gas oil was claimed by both countries, but through persistence, Timor-Leste achieved clarity on the matter,” he added.
Lopes noted that the treaty paved the way for Timor-Leste and Australia to jointly develop a special economic zone, aiming to foster future industrial growth.
He offered this experience as an example, suggesting that the resolution of maritime disputes through diplomatic means and legal frameworks like UNCLOS could serve as a valuable lesson for the kingdom in managing its own maritime concerns.
