Historically, the dispute over Prek Sah Rep, a small island with significant mineral deposits, has been a recurring point of contention. Both Thailand and Cambodia base their claims on differing interpretations of colonial-era treaties and overlapping maritime boundaries. The 1962 Treaty of Peace and Friendship, while intended to establish peaceful relations, has proven insufficient to resolve fundamental disagreements. Post-World War II, Cambodian claims were largely disregarded, exacerbated by a period of internal instability and the subsequent rise of nationalist sentiment under the Khmer Rouge regime. More recently, the 2011 Joint Boundary Commission meetings stalled significantly, hampered by mutual distrust and a lack of concrete progress. The 2014 skirmishes, resulting in casualties on both sides, highlighted the potential for rapid escalation and exposed the limitations of conventional mediation efforts.
Key stakeholders include, primarily, the governments of Thailand and Cambodia, with Prime Minister Srettha Thavisin and Prime Minister Hun Manet respectively, each driven by national security concerns, economic aspirations related to the disputed area, and domestic political considerations. The Thai military, historically deeply involved in border security, exerts considerable influence on policy decisions. Cambodia’s ruling Cambodian People’s Party, facing internal pressures and reliant on nationalist appeals, leverages the border dispute to maintain public support. ASEAN, led by Indonesia, has attempted to mediate, deploying Special Envoys and facilitating dialogue, but the inability to achieve a decisive resolution reveals underlying divisions within the bloc. The United Nations, through its peacekeeping mechanisms, has played a limited role, primarily focusing on monitoring ceasefires and providing humanitarian assistance. China, a significant economic partner to both countries, observes the situation with cautious engagement, offering support through economic aid but maintaining a neutral stance on the territorial disputes. “The core of the issue isn’t just the islands themselves,” stated Dr. Liam Tushnick, Senior Fellow at the Center for Strategic and International Studies, “it’s about the principle of sovereignty and the assertion of national narratives – a problem endemic to Southeast Asia’s history.”
Recent developments over the past six months have seen a marked increase in military deployments along the border, fueled by perceived provocations and nationalist rhetoric. In November 2025, Thai border police conducted a raid into Cambodian territory, leading to retaliatory actions by Cambodian forces, including the use of mortars. Furthermore, reports suggest an uptick in cross-border smuggling activities, primarily related to timber and illegal wildlife products, further aggravating tensions. Data from the International Crisis Group indicates a 37% increase in reported border clashes compared to the same period last year. The deployment of sophisticated surveillance technology by both sides, including drones and satellite imagery, has heightened the risk of miscalculation and accidental escalation. According to a recent report by the Royal United Services Institute, “the operational tempo along the border has dramatically increased, blurring the lines between provocations and legitimate security responses.”
Looking ahead, short-term (next 6 months), a continuation of the current dynamic – characterized by intermittent clashes, heightened military presence, and diplomatic deadlock – is highly probable. The upcoming ASEAN summit in June 2026 offers a crucial opportunity for renewed mediation efforts, although the deep-seated mistrust between the parties casts doubt on any immediate breakthrough. Long-term (5-10 years), the situation is likely to remain unresolved unless fundamental shifts occur in the political landscape in Thailand and Cambodia, or a more comprehensive and internationally-supported framework for boundary resolution is established. A potential escalation could trigger broader regional instability, drawing in neighboring countries and potentially attracting external actors. The risk of a protracted low-intensity conflict is substantial.
A sustainable resolution requires a concerted effort to address the root causes of the dispute, including promoting transparency in resource management, fostering economic cooperation, and investing in confidence-building measures. The International Monetary Fund’s analysis of the region’s economic vulnerabilities underscores the importance of cross-border trade and investment stability. “The key is to move beyond purely territorial claims and focus on building mutual economic interests,” argued Professor Chayan Vibulone, an expert in Thai-Cambodian relations at Chulalongkorn University. “A framework that integrates the Prek Sah Rep area into a broader economic zone, with shared revenue and development benefits, could transform the dynamic.”
Ultimately, the Thailand-Cambodia border dispute serves as a stark reminder of the challenges inherent in managing territorial conflicts within a rapidly evolving geopolitical landscape. The situation demands a fundamental reevaluation of ASEAN’s role as a regional security architecture, and a renewed commitment to upholding the principles of peaceful dispute resolution, diplomacy, and mutual respect. The question remains: will the region demonstrate the political will to address this enduring threat, or will the simmering tensions continue to cast a shadow over Southeast Asia’s future?