Unlocking the Gulf: What the Cambodia–Thailand Maritime Dispute Reveals About Power, Law and the Future of the Gulf

The Cambodia–Thailand maritime dispute has entered a consequential new phase. From September 14-16, 2026, a Conciliation Commission is meeting in Singapore under the UN Convention on the Law of the Sea (UNCLOS), with the Permanent Court of Arbitration serving as Registry.

Cambodia invoked the compulsory conciliation process after Thailand terminated the 2001 Memorandum of Understanding (MoU) concerning overlapping maritime claims. Thailand has claimed that the MoU had not produced sufficient progress and that future discussions should proceed under international law and UNCLOS.

The central question is therefore larger than where a future maritime boundary will ultimately be drawn. It is how Cambodia and Thailand manage contested maritime space while that question remains unresolved — and whether international law can keep competing claims, resources and national interests from becoming another source of confrontation.

The End of the MOU Is Not the End of the Law

The 2001 MOU was a bilateral framework for addressing overlapping claims; it was not itself a final maritime boundary agreement. Its termination does not, by itself, establish a boundary, extinguish either side’s claims or create a legal vacuum. UNCLOS remains the central legal framework.

That distinction matters. The failure of the previous framework should not simply be reduced to a question of which side is responsible. Maritime delimitation involves technical, legal and political sensitivities, including coastal geography, baselines, maritime entitlements and competing economic interests. A new framework should therefore be stronger, clearer and more operational than the previous one.

A fresh framework should also make the process more predictable. It should identify how technical work is conducted, how information is exchanged, how differences are recorded and how incidents are addressed without turning every disagreement into a political crisis. The more predictable the process, the less room there is for misunderstanding or unilateral interpretation.

The gulf also cannot simply be placed on hold while negotiations continue. Fishing, navigation, environmental protection, scientific activity, search and rescue, maritime safety and potential offshore development continue to create practical questions. The objective should not merely be to restore the old MOU, but to build a more effective UNCLOS-grounded framework that preserves both sides’ legal positions while preventing disputes from escalating.

Law Requires Precision, Not Nationalist Rhetoric

One of the most important disciplines in this dispute is to distinguish territorial sovereignty from maritime entitlements and sovereign rights. Continental shelf and exclusive economic zone rights are not identical to sovereignty over land territory. They concern specific rights and jurisdiction under international law.

This distinction strengthens Cambodia’s position rather than weakening it. A maritime boundary should ultimately be addressed through legal and technical analysis: maritime entitlements, coastal geography, applicable baselines, UNCLOS provisions and relevant geographic circumstances. Cambodia therefore has a strong interest in maintaining and strengthening its legal, hydrographic, geographic and historical evidence.

Precision also matters because maritime disputes are vulnerable to political rhetoric. A credible Cambodian position does not require portraying Thailand as acting outside the law, nor does it require Cambodia to abandon its own claims. It requires Cambodia to demonstrate that its claims can withstand legal and technical scrutiny.

Thailand’s Position Creates an Opportunity for a Rules-Based Framework

Thailand has stated that its objective is maritime delimitation and peaceful resolution under international law, and that the 2001 MoU was insufficient. Cambodia can take that position seriously and consistently ask what legal and practical arrangements should govern the disputed area while delimitation remains unresolved.

UNCLOS provides an important starting point. Its provisions concerning maritime delimitation call on states, pending agreement, to make every effort to enter into provisional arrangements of a practical nature and not to jeopardise or hamper the reaching of a final agreement. This does not automatically resolve every question or prohibit every activity. It establishes a principle of restraint and cooperation.

Cambodia could therefore support discussions on practical interim arrangements, where mutually agreed, covering issues such as fisheries, environmental protection, scientific surveys, maritime safety, search and rescue, and offshore activities. If joint development were considered, it should be based on explicit consent, without prejudice to the final delimitation, with clear rules governing operations, revenue, jurisdiction, environmental standards and dispute settlement.

Such arrangements would also give both sides a practical incentive to keep negotiations moving, because responsible interim management can reduce the immediate costs of unresolved claims while leaving the final legal question open.

Cooperation is not recognition. Interim management is not final delimitation.

Cambodia’s Strategic Advantage Is Law

Cambodia and Thailand do not possess identical capabilities. A contest based primarily on naval strength, economic pressure or coercive leverage would not serve Cambodia’s interests. Cambodia’s comparative advantage lies elsewhere: international law, evidence, institutions, diplomacy and strategic patience.

Cambodia does not need to defeat Thailand at sea. It needs to ensure that the maritime dispute cannot be decided by power alone.

That requires sustained technical preparation. Cambodia should maintain a coherent evidentiary record, strengthen hydrographic and geographic expertise, and ensure that its legal arguments are consistent across diplomatic, technical and international processes. Institutional continuity is equally important. Maritime delimitation is rarely resolved by political statements alone; it requires patient work by lawyers, geographers, hydrographers, diplomats and policymakers.

The Economic Stakes Require Prudence

The overlapping claims area is frequently discussed in connection with possible offshore energy resources and the broader economic potential of the gulf. Estimates of potential resource value should, however, be treated cautiously. Potential resources are not the same as proven reserves, commercially recoverable deposits or guaranteed government revenue.

Nevertheless, prolonged uncertainty has an economic cost. Energy security, investment confidence, electricity supply and industrial development matter to Cambodia, just as economic stability and resource interests matter to Thailand. This creates a shared incentive to manage the disputed area responsibly.

Any resource cooperation must also avoid prejudging sovereignty or delimitation. The principle should be simple: economic cooperation, if agreed, must not become a mechanism for either side to establish a unilateral legal advantage.

Avoiding a Second Theatre of Tension

The maritime dispute should also be managed separately from other sensitive Cambodia–Thailand territorial questions. Land-border disputes and maritime delimitation involve different legal and geographic issues, even though their political consequences can interact.

This is particularly important because tensions along the land border have demonstrated how quickly territorial issues can become matters of national emotion, public controversy and security concern. A maritime incident, misunderstanding or unilateral action could similarly acquire a political meaning far beyond its immediate facts.

The two governments therefore have an interest in predictable communication channels and confidence-building measures. Preventing incidents is not a concession. It is a practical safeguard while negotiations continue.

Conciliation a Tool, Not a Substitute for Strategy

The Singapore conciliation process is significant because it places the dispute within an established international legal mechanism. But conciliation should not be misunderstood. It is intended to facilitate an agreed settlement; it is not equivalent to a binding judicial judgment that simply fixes the maritime boundary.

For Cambodia, the value of the process lies not only in its outcome but also in the opportunity to demonstrate legal consistency, good faith and readiness for a rules-based settlement. Cambodia should use the process to clarify its legal position, preserve its rights and encourage practical arrangements that reduce the risk of confrontation.

The broader objective should be a settlement that is lawful, durable and mutually workable.

A Strategic Path Forward

Cambodia’s objectives should therefore be clear: pursue final maritime delimitation under international law; protect its legal claims and evidence; support practical interim arrangements without prejudice; consider mutually agreed joint development only where legally and commercially appropriate; oppose unilateral measures that prejudge the outcome; and maintain diplomatic and technical channels capable of managing incidents.

This is not an anti-Thai strategy. It is a rules-based strategy.

Thailand has legitimate interests in security, maritime access and economic development. Cambodia has legitimate maritime claims and national interests of its own. Recognising the legitimacy of the other side’s interests does not require surrendering one’s legal position. On the contrary, it creates the political space for serious negotiation.

The dispute also presents an opportunity for ASEAN. A contested maritime space in the Gulf of Thailand can become another source of rivalry, or it can demonstrate that neighbouring states can manage difficult disputes through law, restraint and diplomacy. The latter outcome would serve both countries and the wider region.

Cambodia’s strongest position is therefore neither confrontation nor passivity. It is disciplined persistence: prepare the evidence, use the law, engage diplomatically, cooperate where cooperation is possible and prevent temporary arrangements from becoming permanent facts.

The objective should not be to humiliate Thailand or claim a political victory. It should be to secure Cambodia’s lawful maritime interests while preserving peace and creating the conditions for a durable settlement.

Let international law guide the principles. Let evidence establish the case. Let diplomacy negotiate the settlement. Let neither side use power to prejudge the outcome.

That is not an anti-Thai position. It is a rules-based position—and, for Cambodia, a strategically realistic one.

Long Panhavuth is founder and attorney-at-law at Pan & Associates Lawfirm. The views and opinions expressed are his own.