Cambodia and Thailand have commenced compulsory conciliation proceedings in Singapore, marking an effort to resolve their long-running maritime boundary dispute in the Gulf of Thailand. The three-day session, which began yesterday, is being conducted under Article 298 and Annex V of the U.N. Convention on the Law of the Sea (UNCLOS).
The proceedings were initiated by Cambodia in June, shortly after Prime Minister Anutin Charnvirakul's government unilaterally cancelled a 2001 Memorandum of Understanding (MoU) that governed joint offshore energy exploration and the demarcation of maritime boundaries in the disputed area. Prime Minister Charnvirakul denied that the cancellation was linked to land border tensions, instead citing a lack of progress under the agreement.
The initial session yesterday was held behind closed doors, chaired by Katrina Cooper, the head of the Conciliation Commission. Today, a public session featured opening statements from the foreign ministers of both nations, outlining their respective governments' positions.
Cambodian Foreign Minister Prak Sokhonn stated that his government's objective is “to achieve a resolution that serves the peoples of both nations and contributes to peace, cooperation and shared prosperity in the region.” He emphasized that Cambodia chose to initiate compulsory conciliation after the MoU's cancellation to “find a peaceful pathway forward in accordance with international law,” viewing the process as “a means to rebuild trust, not as a form of escalation.”
Thailand's Foreign Minister Sihasak Phuangketkaew affirmed that Thailand “enters this conciliation in good faith, fully mindful of the provisions of UNCLOS,” and “stands ready to engage in this process constructively, with the aim of achieving, with the Commission’s assistance, a negotiated and equitable solution.” However, Phuangketkaew adopted a more combative tone, accusing Cambodia of using international law as a refuge while “repeatedly vilif[ying] Thailand through false narratives, distortion of facts, and unfounded accusations.” He reiterated that Thailand cancelled the 2001 MoU due to its failure to produce “concrete progress” and to “give negotiations a fresh start.” Phuangketkaew also expressed disappointment that Cambodia opted for compulsory conciliation, stating that Thailand had offered direct bilateral talks and consistently believed that “differences between neighbors should be addressed through dialogue.”
The Thai foreign minister also clarified that the conciliation proceedings would concern “only maritime boundary delimitation between Thailand and Cambodia in the Gulf of Thailand” and would not address the island of Koh Kut, which Cambodia claimed a portion of in a 1972 continental shelf claim.
The maritime dispute centers on a 26,000-square-kilometer area in the Gulf of Thailand, known as the Overlapping Claims Area (OCA). This area is believed to contain significant reserves of oil and natural gas, whose exploitation has become increasingly urgent amidst the current global oil supply crisis.
Tensions over the maritime boundary have escalated in conjunction with an intensifying land border dispute between Phnom Penh and Bangkok. This land dispute led to armed conflict twice last year, resulting in nearly 150 deaths and displacing approximately a million people on both sides of the border. Thai nationalist concerns over Koh Kut previously derailed attempts by a former Thai government to negotiate a resolution for the OCA in late 2024 and early 2025, contributing to the land border clashes and fueling calls for the cancellation of the 2001 MoU.
The underlying cause of the maritime dispute is rooted in divergent interpretations of a 1907 land border treaty between Siam and French Indochina, which provided a land point from which both countries have since charted their claims, without delineating the maritime border itself. While the maritime dispute is theoretically simpler to resolve than the land border disagreements—which involve complex French colonial cartography and culturally significant Angkorian temple ruins—the recent armed clashes have severely strained relations, making any agreement, even one facilitating mutual resource exploitation, a significant challenge.
