On June 2, Cambodia formally initiated compulsory conciliation proceedings against Thailand under the United Nations Convention on the Law of the Sea (UNCLOS). The move came after Thailand unilaterally withdrew from a 25-year-old bilateral memorandum of understanding that was designed to settle the maritime boundary and govern the sharing of valuable undersea oil and gas deposits. Thailand has since agreed to participate in the UNCLOS process, a development Phnom Penh has welcomed as a constructive step.
A Precedent for Peaceful Resolution
The significance of this case extends beyond the two countries. It offers the international community—great powers, middle powers, and small states alike—a chance to see effective international law in action at a time when the multilateral rules-based order faces mounting pressure. For the Association of Southeast Asian Nations (ASEAN), it is an opportunity to draw on the region's tradition of mutual support and its reputation as a global model for dispute resolution.
Ten years ago, UNCLOS compulsory conciliation resolved a seemingly intractable maritime dispute between Timor-Leste and Australia. The asymmetry between those two states was stark: Australia's population was 20 times larger, its nominal GDP nearly 500 times greater, and its military expenditure roughly 1,000 times higher. Timor-Leste enlisted international experts to break the deadlock, and despite Australia's initial opposition, a historic treaty was signed within two years. Australia's then-Foreign Minister Julie Bishop praised the outcome, stating that the treaty “reflects the importance of UNCLOS” and “shows how international law can enable countries to resolve their disputes peacefully.”
That precedent speaks directly to Cambodia and Thailand today. The UNCLOS conciliation process will require good faith, consistency, and pragmatism from both sides. In the Timor-Leste case, Australia engaged consistently with the conciliation commission, maintaining bilateral cooperation throughout. Relations between the two neighbors improved as a result, culminating in a permanent maritime boundary treaty.
Energy Resources and Regional Stability
The Cambodia-Thailand dispute is not merely an abstract legal question. It concerns a real maritime area and real energy resources that could contribute to economic security and development for both countries and the wider region. Cambodia is not asking the conciliation commission to impose a one-sided answer; it is asking for the process to address the issue as it is—a maritime-boundary dispute intrinsically linked to the peaceful development of energy resources. As Thailand should not abandon maritime dialogue with Cambodia, both sides must recognize that international law does not require either to abandon national interests, but to pursue them peacefully within a rules-based framework.
The same commitment must extend to the shared land border. The current ceasefire between Cambodia and Thailand remains fragile, and Phnom Penh remains concerned by the situation in occupied areas well inside its territory. Borders and sovereignty must never be altered by force or fait accompli. On land as at sea, steadfast adherence to international law, existing treaties, and dialogue are key to ensuring respect for territorial integrity.
Cambodia attaches great importance to its relationship with Thailand, a close neighbor with a common commitment to regional peace and prosperity. The maritime area must not become another theater of mistrust, and the land border must not see further escalation. Instead, both countries should follow the tradition of how Southeast Asian states resolve difficult disputes—through dialogue and international law.
The Timor-Leste case began with acrimony and ended with agreement. It began with uncertainty and ended with proof that compulsory conciliation under international law can break a deadlock when bilateralism has run its course. Cambodia welcomes Thailand's engagement in the UNCLOS process and asks that all sides engage in good faith. Their peoples, the region, and the world will bear witness.
