ASEAN Summit: Thailand and Cambodia Sign Comprehensive Ceasefire Deal

The Kingdom of Thailand and the Kingdom of Cambodia signed an expanded ceasefire agreement on 26 October 2025, during the annual summit of the Association of Southeast Asian Nations (hereinafter: ASEAN). This formal declaration aims to consolidate the truce previously agreed upon in July, following a five-day border conflict that resulted in dozens of casualties and the displacement of hundreds of thousands of civilians. The signing, overseen by leaders from the region, institutionalises measures to prevent renewed hostilities along the historically disputed 800-kilometre frontier (Reuters; Al Jazeera). The agreement represents a significant diplomatic step for both nations within the ASEAN framework and was conducted at the summit.

The Scope of the Expanded Ceasefire Deal

Concrete Measures for De-escalation

The comprehensive agreement signed by Thai Prime Minister Anutin Charnvirakul and Cambodian Prime Minister Hun Manet goes beyond a mere cessation of fighting and details specific, actionable steps for military de-escalation and confidence-building. As reported by Reuters, the key components of the enhanced ceasefire include:

• Weapons Removal: Both states committed to the removal of heavy and destructive weapons and military equipment from the disputed border areas. This equipment is mandated to be returned to regular military installations, with verification to be conducted by the newly established monitoring teams.
• Prisoner Release: Thailand agreed to the prompt release of 18 Cambodian soldiers who were held prisoner, a measure intended to build mutual confidence and trust between the two states.
• De-mining Efforts: Both nations committed to coordinating humanitarian de-mining operations in the border areas to protect civilian populations and facilitate socio-economic development.
• Restraint from Rhetoric: The agreement mandates that both sides refrain from disseminating or promoting false information, accusations, or harmful rhetoric, whether through official or unofficial channels, to de-escalate tensions and foster an environment conducive to peaceful dialogue.

ASEAN Monitoring Mechanism

A crucial institutional element of the expanded ceasefire is the establishment of an ASEAN Observer Team (AOT). The two states signed the terms of reference for the AOT, which will comprise personnel from ASEAN member states. The AOT is tasked with monitoring and verifying the full and effective implementation of all terms of the ceasefire, ensuring that the agreed-upon de-escalation measures are practically carried out along the frontier (Reuters; TRT World). This deployment of a regional observer mission reinforces ASEAN’s role in managing internal conflicts and maintaining regional stability, a mission that has faced historical challenges within the bloc (a context which can be understood by consulting Essydo’s Yaba: The Drug That Is Shaping Geopolitics In Southeast Asia for a perspective on regional security issues).

Concluding Forecast/Outlook

The signing of the comprehensive ceasefire declaration under the auspices of ASEAN is a formal step toward institutionalising peace between Thailand and Cambodia, but its long-term success will hinge on two primary challenges related to enforcement and political will.

First, the institutional challenge lies in the effective operation of the ASEAN Observer Team. The success of the AOT requires not only the full cooperation of both Thai and Cambodian militaries but also the sustained commitment of resources and political capital from the broader ASEAN bloc. Should the removal of heavy weapons and de-mining efforts face operational delays or political obstructions, the AOT’s credibility would be undermined, risking a return to the armed confrontations that characterised the situation in July.

Second, the structural challenge remains the unresolved border demarcation. The signed agreement reinforces commitments to settle the fundamental border dispute through peaceful means and establishes bilateral mechanisms, such as the Joint Boundary Commission. However, the agreement itself does not resolve the contested claims. The political commitment of both governments to prioritise the framework of the ceasefire over nationalistic impulses in managing the undemarcated zones will be the ultimate determinant of whether the agreement serves as a foundation for a lasting peace or merely a temporary cessation of hostilities.