Thailand Joins Cambodia's $300 Billion Maritime Arbitration Amid Border Tensions

The relationship between Cambodia and Thailand remains strained despite six months passing since the end of their military clashes. Both countries are now turning to international arbitration mechanisms to address maritime disputes, while disagreements over land borders continue without clear resolution.

On June 5, Thailand announced its acceptance to participate in Cambodia’s initiative for United Nations-led arbitration concerning the maritime dispute between the two nations. This development coincides with the suspension of bilateral efforts to resolve land border conflicts, reflecting ongoing instability between the neighboring states.

Although a ceasefire remains in effect, tensions along the border have not fully eased, according to Foreign Policy. In May, Thailand accused Cambodian forces of firing along the border, while Cambodia countered by accusing Bangkok of occupying areas previously recognized as Cambodian territory.

Thailand has kept border crossings closed despite the economic consequences, and peace talks concerning the land border have stalled for months. Efforts by the Association of Southeast Asian Nations (ASEAN) to push both sides toward a lasting agreement have so far failed.

Observers warn that the current situation risks turning the border dispute into a prolonged frozen conflict, with the possibility of renewed clashes remaining, though unlikely at present.

Maritime Dispute and Resource-Rich Waters

Alongside land disagreements, the maritime dispute stands out as a key unresolved issue. It involves a sea area rich in natural resources valued at approximately $300 billion, over which both Cambodia and Thailand claim sovereignty.

Cambodia’s decision to invoke the compulsory conciliation mechanism under the United Nations Convention on the Law of the Sea (UNCLOS) followed Thailand’s cancellation of a 2001 agreement that had aimed to establish a framework for jointly developing resources in the contested area.

This arbitration mechanism is rarely used; it was previously invoked only once in Southeast Asia in 2016 to assist in maritime boundary delimitation between Australia and Timor-Leste.

Thailand’s Reservations and Legal Considerations

Despite agreeing to participate in the arbitration, Thailand has expressed clear reservations, having previously preferred bilateral solutions it deemed more aligned with its interests. Thai Foreign Minister Sihasak Phuangketkeow stated that Thailand requested Cambodia to allow an additional six months for direct talks, signaling a desire to keep bilateral negotiations open.

Analysts suggest Thailand’s participation does not necessarily indicate a shift in its stance on the maritime dispute but may aim to influence the arbitration process and maintain a role in determining the contested area's future.

Respect for international law is an important factor for Bangkok, especially in Southeast Asia, where legal institutions and peaceful dispute resolution mechanisms are highly valued.

Furthermore, the outcomes of the conciliation process are not legally binding on the parties involved. The UNCLOS explicitly states that the commission’s report, findings, or recommendations do not impose legal obligations on the states concerned, reducing the political risks associated with participation.

Regional Political and Security Developments

The Cambodia-Thailand border crisis coincides with several political and security developments in the region. On June 3, former Thai Prime Minister Thaksin Shinawatra received a royal pardon for corruption and conflict of interest charges after a political career spanning decades since his first election in 2001 and his ousting by a military coup in 2006.

Thaksin had returned to Thailand in 2023 and was sentenced to eight years in prison, later reduced to one year.

In Malaysia, the states of Johor and Negeri Sembilan are preparing for early elections in July and August amid increasing competition between major parties within both the ruling coalition and the opposition.

Meanwhile, the Philippines experienced a 7.8 magnitude earthquake on June 8 in Mindanao, resulting in at least 35 deaths and over 200 injuries. Landslides caused at least 14 fatalities, prompting authorities to deploy the military for rescue operations and suspend schooling in affected areas.

In Singapore, the government continues to tighten regulations on electronic cigarettes. Users face fines up to 7,800 Singapore dollars, sellers risk penalties exceeding 155,000 Singapore dollars and imprisonment up to six years, and smugglers may be fined up to 233,000 Singapore dollars and jailed for up to nine years.

While attention focuses on the maritime arbitration between Cambodia and Thailand, unresolved land border disputes remain the most significant threat to bilateral stability amid the absence of a comprehensive political settlement addressing the long-standing conflict’s roots.