Thailand and Cambodia begin UN-backed conciliation over maritime claims

Cambodia has expressed its willingness to engage in talks with Thailand to jointly develop offshore resources, without waiting for a final resolution of their maritime boundary dispute. This comes as the two nations convened their inaugural UNCLOS conciliation meeting in Singapore. Cambodian Foreign Minister Prak Sokhonn emphasized Phnom Penh's ultimate objective of a treaty establishing a singular maritime boundary.

In the event of a deadlock over delimitation or joint development, the country may seek the conciliation commission's recommendations for a future settlement. Thailand, however, has not officially backed the joint-development proposal. Deputy Prime Minister and Foreign Minister Sihasak Phuangketkeow stated that Bangkok sought a just boundary, having previously advocated for six months of direct negotiations, succeeded by mediation if no agreement materialized.

The maritime boundary disagreement stems from overlapping continental-shelf claims filed by Cambodia in 1972 and Thailand in 1973, covering roughly 26,000 square kilometers in the Gulf of Thailand. This area is believed to harbor significant oil and natural gas reserves. The two governments signed a 2001 Memorandum of Understanding (MOU), or MOU 44, to establish a negotiation framework, linking delimitation north of latitude 11°N with potential joint resource development to the south, without either side relinquishing their claims.

The framework yielded only a limited number of meetings and no agreement over the subsequent 25 years. The issue gained heightened political sensitivity due to armed clashes along the land border in 2025. Prime Minister Anutin Charnvirakul and the Bhumjaithai party campaigned to repeal the MOU, arguing it had been ineffective and raised sovereignty concerns.

Cambodia ratified UNCLOS on February 6, 2026, gaining access to the convention's compulsory conciliation mechanism. The Thai cabinet subsequently terminated the MOU on May 5. Thailand indicated a desire to recommence discussions under UNCLOS guidelines, while Cambodia contended that the termination had closed the existing bilateral avenue.

Phnom Penh subsequently announced its intent to pursue compulsory conciliation and formally initiated the process later that month. Thailand initially objected to the move but agreed to participate, appointing two conciliators in June. Sihasak clarified that the proceedings would focus solely on maritime delimitation in the Gulf of Thailand, excluding sovereignty over Koh Kood or other land territories.

He reaffirmed Thailand's position under its 1973 royal proclamation and dismissed Cambodia's 1972 continental-shelf claim as lacking legal foundation. The two sides also disagreed on who should bear responsibility for the negotiation breakdown. Cambodia attributed it to Thailand's unilateral MOU termination; Thailand blamed Cambodia for rejecting a proposal to restart direct talks.

The conciliation commission lacks authority to impose decisions. Its findings and recommendations are non-binding, requiring the two nations to negotiate any maritime boundary treaty or joint-development agreement independently. Both parties pledged to participate constructively and strive for a peaceful resolution.