Cambodia’s Three-Track Strategy for Peace with Thailand

Cambodia-Thailand border disputes are complex as they are rooted in colonial-era treaties, competing maps, contested temples, unsettled demarcation and recurring nationalism. Armed clashes, partly driven by domestic political developments in both countries, erupted in July and December 2025. The rise of ultranationalist groups is making bilateral reconciliation and solutions harder to reach. The recent episodes also showed that the disputes can quickly turn violent with high economic costs, causing particularly significant damage to both economies.

From Phnom Penh’s perspective, the key challenge now is to demand that Thailand withdraw its troops while rejecting attempts to alter borderlines through force, coercion or fait accompli. Phnom Penh’s approach has three tracks: bilateral mechanisms, international legal processes and third-party mediation. For this approach to be effective, however, the two sides need to resolve their border demarcation issue first.

Cambodia’s first track is bilateral negotiation through existing mechanisms. Prime Minister Hun Manet stated in April 2026 that “even if only one percent” of diplomatic opportunity remained, Cambodia is “committed to fully exhausting all peaceful mechanisms rather than resorting to prolonged conflict”.

The existing bilateral mechanisms include the Joint Boundary Commission (JBC), established under the 2000 Memorandum of Understanding (MoU) on land boundary survey and demarcation. The JBC is the main technical body for survey, mapping and demarcation. It works alongside the General Border Committee (GBC) on security and military issues and the Regional Border Committee (RBC) on local incidents or tensions. These mechanisms are often slow and constrained by domestic political pressures, yet they are indispensable for confidence-building, preventive diplomacy and the pursuit of practical technical solutions.

The second track concerns international legal processes. The 1904 and 1907 Franco-Siamese instruments and related maps are central to Cambodia’s approach to border demarcation. In 1962, the International Court of Justice (ICJ) ruled that the Preah Vihear Temple fell within Cambodian territory. In 2013, the Court clarified that Cambodia had sovereignty over the whole promontory. The rulings continue to shape Phnom Penh’s strategic thinking. They have compelled Cambodia to believe that international adjudication, though time-consuming, can provide legal solutions where bilateral talks are blocked by nationalism, political shifts or competing historical narratives.

Renewed border tensions in 2025 further strengthened this logic. In May, a Cambodian soldier was killed and disputes escalated around several contested areas. The following month, Cambodia brought the border issues concerning the Mom Bei areas and the Tamoan Thom, Tamoan Touch and Ta Krabey temples before the ICJ. Thailand has rejected the ICJ’s jurisdiction and refused to go to court because doing so would undermine its sovereignty and territorial integrity.

Moving forward, political will, good faith, reliable hotline communication and confidence-building measures are essential to creating a solid foundation for bilateral negotiations.

Following Thailand’s termination of the MoU on overlapping maritime claims in the Gulf of Thailand in May 2026, Phnom Penh responded by initiating compulsory conciliation under the 1982 United Nations Convention on the Law of the Sea (UNCLOS). Thailand subsequently agreed to participate in the process. This mechanism is expected to provide a peaceful and rules-based framework for resolving the outstanding bilateral maritime disputes. Although compulsory conciliation under UNCLOS is designed to produce recommendations rather than a binding judgment, it can still serve important purposes. It internationalises the issue, creates a structured process, reduces the risk of unilateral action and places both parties under greater diplomatic scrutiny.

The third track is third-party mediation. Cambodia has sought support from ASEAN, China, the US and other partners during periods of armed conflict. Malaysia, as the ASEAN chair in 2025, played a crucial role in facilitating ceasefire efforts. Malaysian Prime Minister Anwar Ibrahim’s mediation helped create diplomatic space when direct communication between Phnom Penh and Bangkok was cut off. The involvement of China and the US added strategic weight to the process. In particular, US President Donald Trump was actively involved in this process.

The July 2025 ceasefire showed the effectiveness of coordinated diplomacy. It was followed by the Kuala Lumpur peace accord in October 2025, which, among other things, saw the two sides agree to de-escalation and confidence-building. However, these agreements failed to prevent a new round of armed conflict largely due to the lack of credible monitoring, verification and enforcement. The second round of armed clashes erupted in December on a much larger scale. The conflict lasted 21 days and displaced more than half a million people. China’s subsequent engagement was decisive. Both Cambodia and Thailand have accepted China’s role as a mediator.

The China-led trilateral meeting in Yunnan in December 2025, also known as the Fuxian Consensus, helped restore the ceasefire. The process was buoyed by quiet diplomacy and high-level strategic engagement by the Chinese leadership. China also offered to provide a platform for both sides to engage in more comprehensive and effective communication and trust-building, including through track-two diplomacy. In parallel, China provided humanitarian assistance to communities affected by the conflict and supported humanitarian demining efforts along the border areas.

Cambodia’s approach, therefore, combines bilateral and multilateral frameworks while placing primary emphasis on bilateral settlement mechanisms. Cambodia has sent multiple diplomatic notes proposing the convening of a special JBC meeting and the deployment of Joint Survey Teams to resume field operations. However, the Thai side has requested several postponements. Thailand cited internal procedures, elections, the appointment of a new prime minister, cabinet formation and the need to approve a new JBC leadership structure. More recently, Thailand did not warm to Cambodia’s decision to initiate compulsory conciliation.

Looking Ahead

Moving forward, political will, good faith, reliable hotline communication and confidence-building measures are essential to creating a solid foundation for bilateral negotiations. There are some positive signs of a revival in bilateral negotiations. It is therefore fundamental to establish stable and effective channels of communication between Phnom Penh and Bangkok. Bilateral cooperation in combating online scams should be further strengthened, while people-to-people exchanges and economic cooperation should be restored and gradually normalised.

But cooperation on scams and tourism cannot substitute for progress on the border issue. Until the JBC resumes substantive boundary surveys and the disputed temple and maritime areas move from contention to formal demarcation, the current ceasefire, like the ones before it, will remain tenuous and fragile rather than permanent.

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