Sihasak Phuangketkeow, Thailand’s deputy prime minister and foreign minister, in Paris for an OECD ministerial meeting, said in a June 2 interview published the next day by Nation Thailand that Cambodia’s turn to compulsory conciliation under the UN Convention on the Law of the Sea would carry well beyond the maritime file. If Cambodia pursued the mechanism, he said, it was “unavoidable that this will affect talks on restoring relations, border security and the beginning of discussions on boundary issues,” and on the stakes he went further: “If Cambodia goes down this path, we will go all the way.”
The filing he warned against became available because of an earlier Thai decision. On May 5 the Thai Cabinet terminated the 2001 memorandum of understanding, the framework both governments had used for a quarter-century to manage the overlapping area, saying it had produced no progress and that Thailand would treat UNCLOS as a reference for future negotiations. The memorandum contained no provision for its own termination. The bilateral channel Sihasak now faults Cambodia for bypassing is the one Thailand’s own Cabinet closed.
Bangkok’s response on June 2 ran in two registers. Prime Minister Anutin Charnvirakul, speaking after a Cabinet meeting, told reporters, “Why do we need to counter it?” and said Thailand “does not need to change its stance because no one has raised this issue at all.” One was a prime minister at a Cabinet stakeout treating the filing as nothing to answer, the other a foreign minister abroad attaching consequences to it, both the same day.
Cambodia’s notice to Thailand and the UN Secretary-General named Foreign Minister Prak Sokhonn as its agent and appointed Danish diplomat Peter Taksøe-Jensen and French academic Jean-Marc Thouvenin as conciliators, toward a five-member commission whose recommendations would bind neither side.
While the 2001 memorandum was in force, it gave Thailand a strong argument that the two countries had already committed the dispute to an agreed bilateral channel, the standing kind of arrangement that, under Article 298 of UNCLOS, keeps the convention’s compulsory-conciliation proviso from operating. Thailand’s declaration to the UN rules out binding adjudication of the sea boundary, and Cambodia filed the same exclusion when it ratified the convention this year, so neither can take the other to a court or an arbitral tribunal over the line itself. What those declarations do not exclude is conciliation under Annex V, a non-binding process a party can trigger once negotiations have failed. Ending the 2001 framework removed the bilateral-agreement argument that had kept that proviso shut. The route Cambodia used on June 2 is the one the May 5 termination opened.
Thailand presents UNCLOS as a reference for talks it wants to hold directly, on a fresh basis, after clearing away the 2001 framework. Cambodia has treated it as a process to begin now. Hun Manet said the filing was meant to protect Cambodia’s sovereignty and maritime rights under international law. The two governments are reading the same convention in opposite ways, one as the backdrop to bilateral negotiation, the other as the forum for it.
The Article 298 proviso opens that route only where a dispute postdates the convention and where negotiations have failed to settle it within a reasonable time, conditions a commission tests for itself before going further. The same proviso excludes any dispute that necessarily involves an unsettled question of sovereignty over land or an island, the kind of objection Thailand can raise to argue a maritime claim cannot be cut cleanly from a territorial one, given how the overlapping area is drawn around the Thai island of Koh Kut. Cambodia carries the burden of clearing those gates, and it carries Sihasak’s charge that it turned to an outside body before exhausting talks at home.
Compulsory conciliation takes time, Sihasak argued, citing the only prior use of the mechanism, between Timor-Leste and Australia, which ran close to two years. “That means for another two years, we will not be able to delimit the maritime boundary or jointly develop the overlapping area. So why not try negotiations first?” he said. Direct talks, in his account, could reach agreement sooner, and the outcome of conciliation would bind neither side in any case. “So why don’t we talk first and see whether we can make any progress before entering these mechanisms?”
That process ran from a notice in April 2016 to a maritime boundary treaty signed in March 2018, slow against a single round of talks, but it broke a deadlock direct negotiation had not resolved in decades and ended in a binding agreement rather than foreclosing one. Sihasak holds up the case as the cautionary two-year example. The diplomat who chaired its commission, Peter Taksøe-Jensen, is the conciliator Cambodia has now named to its own.
Sihasak tied the conciliation to relations, border security and land-boundary talks, and said Cambodia had “closed the door on many things, including talks on maritime boundaries.” No cancellation of the Joint Boundary Commission, no postponement, and no formal note turning that warning into policy has been published. The two countries remain under the ceasefire in place since late December, after clashes along their shared border last year that killed close to 150 people.
The area in dispute covers roughly 26,000 square kilometres of the Gulf of Thailand, estimated to hold nearly 12 trillion cubic feet of natural gas and substantial oil. The roughly $300 billion value carried across the reporting traces to a 2024 projection by Pichai Naripthaphan, a former Thai energy minister, a gross figure for resources in the ground rather than a measure of what either state could recover. The 2001 framework had bound delimitation and joint development together as one package, so ending it closed both tracks at once.
Thailand’s Ministry of Foreign Affairs had issued no formal comment on the filing by the time Cambodia announced it on June 2. Sihasak cut his Paris trip short and is due back in Bangkok on June 5 to brief foreign diplomats and hold a news conference, where the Thai position is likely to be set out more fully. Under the procedure, Thailand has 21 days from receiving Cambodia’s notice to name two conciliators of its own; failing that, Cambodia can ask the UN Secretary-General to appoint them. The bilateral framework that had kept the dispute out of that mechanism is the one Thailand’s own Cabinet ended on May 5.