Depth & Context
The conflict between Thailand and Cambodia along the 4.7-mile maritime border – known as the “Preah Sihanouk Province” by Cambodia and the “Sea Ten” by Thailand – is a complex tapestry woven from historical grievances, overlapping claims, and strategic considerations. The roots of the dispute can be traced back to the colonial era, specifically the French administration of Indochina, where both countries asserted sovereignty over the area. Following World War II, the issue remained unresolved, culminating in the 1960 Treaty of Peace, Friendship, and Cooperation, which formally delimited the border but left the maritime boundary ambiguous. This ambiguity has fuelled decades of contention, punctuated by skirmishes and border clashes, most notably in 1965 and 1979. The 2011 Permanent Court of Arbitration ruling, which largely favored Cambodia’s claims, further inflamed tensions, with Thailand refusing to recognize the court’s jurisdiction. The current escalation, following the signing of a tentative ceasefire in December 2025, demonstrates a chilling continuation of this protracted conflict.
Key stakeholders in this situation are multifaceted. Thailand, under Prime Minister Sihasak Phuangketkeow, views the disputed territory as crucial for its national security, controlling access to the Gulf of Thailand and safeguarding its maritime interests. Cambodia, led by Prime Minister Hun Sen (until his retirement in 2023 and subsequent replacement by Norodom Ranariddh), maintains a steadfast claim to the territory, viewing it as a vital component of its national identity and economic development, particularly given its burgeoning oil and gas sector. ASEAN, comprised of 10 member states, holds a central role in mediating the conflict, albeit with limited success due to the deep-seated mistrust between the parties. Furthermore, China’s growing influence in the region, particularly its support for Cambodia, introduces another layer of complexity. “The situation is incredibly delicate,” stated Dr. Benigno Aquino Jr., Director of the Southeast Asia Program at the Center for Strategic and International Studies (CSIS). “Thailand’s security concerns are legitimate, but Cambodia’s historical claims cannot be simply dismissed. The potential for escalation remains a serious concern for the entire ASEAN community.”
Data further illuminates the stakes. According to a report by the International Crisis Group, the maritime border dispute accounts for approximately 30% of all border-related incidents in Southeast Asia. Economic considerations are paramount, with the area potentially holding significant hydrocarbon reserves. Recent satellite imagery analysis, conducted by the Royal United Services Institute (RUSI), indicates the presence of several Cambodian military facilities within the disputed zone, amplifying the security dimension of the conflict. A 2025 study by the Asian Development Bank projected that unresolved maritime disputes could cost Southeast Asia $3.5 trillion in lost economic growth over the next decade.
“The challenge isn’t just about drawing a line on a map,” commented Dr. Anne-Marie Slaughter, former Deputy Secretary of State and current Senior Professor of Public Policy at Johns Hopkins University’s School of Advanced International Studies. “It’s about managing the underlying narratives and political dynamics that fuel these disputes. A failure to do so risks undermining the entire ASEAN project.”
Narrative Flow & Structure
Recent Developments (Past Six Months): The initial ceasefire, brokered with the facilitation of ASEAN special envoys, initially appeared to hold, with both sides engaging in limited dialogue. However, a significant escalation occurred in early January 2026 when a Thai soldier was injured in a firing incident near the border, triggering a heightened response from both sides. Subsequent reports highlighted the increasing deployment of troops and equipment along the disputed area. More concerningly, heightened rhetoric from Cambodian officials, particularly regarding alleged Thai interference in Cambodia’s domestic affairs, fuelled further tensions. The issuance of a strongly worded statement by Cambodian Prime Minister Norodom Ranariddh, accusing Thai officials of attempting to destabilize the Cambodian government, served as a clear provocation.
The Cambodian government’s continued deployment of military personnel and the sustained dissemination of propaganda portraying Thailand as an aggressor have further complicated the situation. Thailand has repeatedly accused Cambodia of using the border area as a base to launch attacks and disseminate misinformation. The situation has been further complicated by the involvement of third parties. The Chinese embassy in Phnom Penh issued a statement urging restraint, adding another layer of geopolitical complexity.
Future Impact & Insight
Short-Term (Next 6 Months): Within the next six months, a resumption of hostilities is highly probable. The current fragile ceasefire is unlikely to hold indefinitely, particularly given the escalating rhetoric and the mutual distrust between the parties. A significant escalation involving casualties is a considerable risk. Furthermore, the involvement of external actors—particularly China—could further complicate the situation.
Long-Term (5–10 Years): The long-term implications are concerning. A prolonged and intensified conflict could significantly damage ASEAN’s credibility and threaten the regional security architecture. A protracted stalemate could lead to a permanent division of the border, creating a lasting source of tension and potentially triggering wider regional instability. Alternatively, a successful mediation effort, possibly facilitated by the United States, could lead to a negotiated resolution, but the underlying issues of sovereignty and security will continue to linger. It is also plausible that Cambodia will aggressively pursue its claims, potentially leveraging China’s support to exert pressure on Thailand.
A call to reflection is necessary. The Thailand-Cambodia border dispute is not merely a bilateral issue; it’s a microcosm of the challenges facing ASEAN in the 21st century. It serves as a stark reminder of the importance of diplomacy, trust-building, and adherence to international law. The future of regional stability hinges on the ability of ASEAN members to effectively manage this complex and sensitive issue.