• Thailand will join a UN arbitration process initiated by Cambodia regarding a maritime boundary dispute.
• The dispute involves around 26,000 sq km of sea in the Gulf of Thailand, valued at approximately $300 billion.
• Thailand has suspended further two-way discussions while following international arbitration protocols.

On June 5, Thailand announced its decision to join a UN arbitration process initiated by Cambodia to resolve a long-standing maritime boundary dispute. This move comes after Cambodia launched a compulsory conciliation process under the United Nations Convention on the Law of the Sea (UNCLOS), following Thailand's unilateral decision to end a 2001 framework agreement for talks regarding the contested area. Both nations have claimed ownership of approximately 26,000 sq km (10,000 sq miles) of maritime territory in the Gulf of Thailand, which is estimated to contain nearly 12 trillion cubic feet of natural gas and large stores of oil, collectively worth around $300 billion, according to Bangkok Post, South China Morning Post, and Reuters.

Thai Foreign Minister Sihasak Phuangketkeow indicated that while Thailand will participate in the UN-mediated process, further two-way discussions to settle the borders have been halted. Sihasak expressed disappointment over Cambodia's intent to address resource-sharing issues within the arbitration talks, suggesting that bilateral negotiations could have been more constructive. He stated, “I told my Cambodian colleagues, ‘Why don’t we give talks a chance? Six months or something?’” highlighting a preference for direct dialogue before engaging in compulsory mediation, according to Bangkok Post, South China Morning Post, and Reuters.

Following Cambodia's announcement of the compulsory conciliation process, which employs a five-member panel for non-binding recommendations, the diplomatic ties between the two nations remain strained. A representative from Cambodia asserted that past two-way talks had been exhausted, urging Thailand to engage in the process with “good faith.” Despite joining the UN arbitration, Thai Prime Minister Anutin Charnvirakul stated there would be no further discussions or cooperative agreements until the dispute is resolved, emphasizing that “from now on there will be no more talks… or other forms of cooperation,” as reported by Bangkok Post, South China Morning Post, and Reuters.

Border relations have heightened in recent years, with two significant clashes last year resulting in nearly 150 fatalities and displacing around 300,000 people. Even though a ceasefire was reached in December, the closure of all border gates between Thailand and Cambodia persists. Nevertheless, experts point out that resolving this dispute might take considerable time through the UN-backed process, contrasting it with previous successful resolutions, such as East Timor's maritime dispute with Australia, which was settled in under two years, according to Bangkok Post, South China Morning Post, and Reuters.