Thailand to Halt Bilateral Talks During Mediation

Thailand will join a United Nations arbitration process to resolve a maritime boundary dispute with Cambodia, according to Foreign Minister Sihasak Phuangketkeow on June 5, 2026. This decision follows Cambodia’s invocation of compulsory conciliation under the United Nations Convention on the Law of the Sea (UNCLOS) to settle the contested area.

The move marks a shift in diplomatic strategy after Thailand unilaterally ended a 2001 framework pact for boundary talks in May 2026. While Bangkok has agreed to the U.N.-backed process, the government is simultaneously freezing other diplomatic channels regarding its borders.

What is at stake in the Thailand-Cambodia maritime dispute?

For more than 25 years, Thailand and Cambodia have both claimed a maritime belt in the Gulf of Thailand covering approximately 26,000 square kilometers, or 10,000 square miles. The dispute is driven by the significant natural resources estimated to be within the contested zone.

According to reporting from Reuters, the area is estimated to hold large volumes of oil and nearly 12 trillion cubic feet of natural gas. The total value of these resources is estimated at $300 billion.

Why is Thailand halting other bilateral talks?

Foreign Minister Sihasak Phuangketkeow announced on June 5, 2026, that Thailand will cease all other bilateral border talks while the U.N. mediation is in progress. As part of this stance, Thailand is also keeping its border gates shut.

This decision follows tensions that escalated after intense border clashes occurred in 2025. The Thai government’s current approach suggests a consolidation of diplomatic efforts into the single U.N. channel rather than pursuing parallel two-way negotiations.

How does the UNCLOS conciliation process work in this case?

Cambodia triggered the compulsory conciliation process under the United Nations Convention on the Law of the Sea (UNCLOS) this week. This mechanism allows a state to seek a resolution when bilateral negotiations fail or are terminated.

Thailand will send two representatives to the negotiations, according to Sihasak Phuangketkeow. However, the Thai Foreign Minister expressed disagreement with how Cambodia intends to use the process.

Sihasak Phuangketkeow told Reuters that he is dismayed that Cambodia intends to use the talks to address resource sharing. He indicated that he had previously suggested a different timeline to his Cambodian counterparts.

I told my Cambodian colleagues, ‘Why don’t we give talks a chance? Six months or something,’ Sihasak Phuangketkeow told Reuters. ‘If we cannot make progress, then we can agree on the next step, which of course includes compulsory conciliation, but it also includes voluntary conciliation.’

The transition to compulsory conciliation follows the collapse of the 2001 framework, which had served as the primary vehicle for bilateral discussions for over two decades before Thailand ended the pact in May 2026.