The Thailand-Cambodia border conflict has once again drawn international attention in 2025 as long-standing territorial disputes, political instability, and strategic miscalculations have combined to trigger one of the most serious military escalations between the two Southeast Asian neighbours in more than a decade. What began as a deadly skirmish in May 2025 has grown into sustained military confrontations, intense diplomatic battles, and fierce information warfare, underlining the depth of unresolved historical grievances and contemporary geopolitical tensions between Thailand and Cambodia.
Historical Roots of the Border Dispute
Thailand and Cambodia share more than 800-kilometre-long border that has been a site of periodic tensions, shaped largely by colonial-era cartography. The origins of the modern dispute lie in a 1907 map drawn during the period when Cambodia was under French colonial rule. This map delineated the boundary between French-controlled Cambodia and Siam (modern-day Thailand). Cambodia has consistently used this map to assert territorial claims, whereas Thailand disputes its accuracy and argues that it is vague and inconsistent with the agreed watershed line.
The most contentious disputes have historically arisen around ancient Khmer temple sites located near the border. Chief among these is the Preah Vihear temple, an 11th century Hindu shrine dedicated to Lord Shiva, perched dramatically on a cliff between Cambodia’s Preah Vihear province and Thailand’s Sisaket province. Thailand occupied the temple area after Cambodia gained independence in 1953, arguing that French cartographers had mistakenly placed it within Cambodian territory. Cambodia took the dispute to the International Court of Justice (ICJ). The ICJ, in 1962, awarded sovereignty over the temple to Cambodia. Thailand reluctantly accepted the verdict after initial military resistance.
The issue resurfaced in the 21st century when UNESCO declared the Preah Vihear temple a World Heritage Site in 2008. Thailand opposed this move, fearing it would strengthen Cambodia’s territorial claims. The decision led to deadly border clashes in 2011 that left about 20 people dead and displaced thousands. Cambodia returned to the ICJ, which reaffirmed its earlier ruling in 2013 and created a demilitarised zone around the temple. Thailand, however, rejected the court’s jurisdiction, keeping the border issue unresolved.
Another sensitive location is Prasat Ta Muen Thom, a Khmer temple complex situated along the border between Thailand’s Surin province and Cambodia’s Oddar Meanchey province. This archaeological site, built by King Jayavarman VII, includes three structures: Prasat Ta Muen Thom, the main temple made of sandstone and feature a shivlinga as well as libraries, Prasat Ta Muen, a Mahayana Buddhist religious site meant to offer refuge to travellers, and Prasat Ta Muen Tot, a hospital shrine for the local community. Both countries have laid competing claims to this temple complex as well, adding further layers to the territorial disagreements.
Also contested is the Phu Makhuea hill (or Phnom Trap), located near Preah Vihear. Control over this hill has changed during the 2025 conflict, with Thai troops reportedly capturing it in late July, raising the Thai flag there.
Escalation of Tensions in 2025
The latest round of conflict began in May 2025 when a skirmish between Cambodian and Thai troops in a contested border area led to the death of a Cambodian soldier. Both sides accused each other of violating territorial sovereignty but initially pledged to de-escalate. However, nationalist rhetoric quickly intensified and both governments adopted retaliatory measures that hardened positions.
Thailand imposed strict border restrictions, allowing only essential crossings, such as for students and medical patients. Cambodia retaliated by banning Thai films, suspending Thai internet links, halting imports of Thai fruits, vegetables, fuel, and gas and boycotting some electricity supplies from Thailand. These tit-for-tat moves reflected the hardening of political attitudes on both sides.
The situation sharply deteriorated in mid-July 2025, when Thai authorities accused Cambodia of laying new anti-personnel landmines inside Thai territory along agreed safe paths. On July 16 and 23, 2025, Thai patrol soldiers were injured in explosions. Thailand condemned these actions as violations of its sovereignty and international law, citing the Ottawa Convention banning such mines, which both countries have signed. Cambodia dismissed these accusations as baseless, attributing the explosions to many unexploded mines and other ordnance that remain in the area as a legacy of 20th-century wars and unrest.
On July 24, 2025, the conflict entered a dangerous new phase. Cambodia launched a rocket barrage into Thailand in the morning, marking the first use of heavy artillery in this cycle of hostilities. Several Thai civilians were killed. Thailand responded with F-16 air strikes on Cambodian military positions, claiming to have destroyed two Cambodian regional military support units. Fights broke out at six locations along the border prompting evacuation of Thai border residents. Thailand further accused Cambodia of using drones for surveillance near the Prasat Ta Muen Thom temple, alleging that initial clashes had occurred in that vicinity. Cambodia disputed this, insisting its forces acted in self-defence against a Thai incursion and drone deployment. By late July, the fighting had left dozens dead and displaced hundreds of thousands of civilians.
A Malaysian-mediated meeting in Kuala Lumpur on July 28, 2025, produced an immediate and unconditional ceasefire; Malaysia chaired the talks and both the United States and China encouraged the process. The ceasefire and subsequent diplomacy helped halt the heaviest fighting, though accusations of violations continued afterwards.
Political Dimensions of the Conflict
Domestic politics in both countries have significantly shaped their respective strategies. In Thailand, Prime Minister Paetongtarn Shinawatra faced a major political crisis in early July when a leaked phone call with former Cambodian Prime Minister, Hun Sen, was made public. In this call, she referred to Hun Sen as ‘uncle’ and criticised Thai military leadership. These remarks were framed as disrespectful to the national sovereignty. The Thai Constitutional Court suspended her, sparking protests and leading to the withdrawal of a key coalition partner, the Bhumjaithai Party, which accused her of being soft on Cambodia. Former Defence Minister Phumtham Wechayachai was appointed as acting prime minster. This domestic turmoil weakened Thailand’s ability to present a unified stance.
On the Cambodian side, Hun Sen, although officially succeeded by his son, Hun Manet, in 2023, continues to wield considerable power as Senate president. He has used the crisis to consolidate his political influence. From the outset, Hun Sen actively shaped the narrative, posting frequent messages and images in Khmer and English on Facebook, taunting the Thai government, along with photos that showed him in army uniform or poring over military maps. This portrayed him as a strong defender of Cambodian sovereignty. He has been maintaining strong control over the army, ruling party, and media, allowing him to coordinate Cambodia’s response far more effectively than the divided Thai establishment.
Thailand’s civil-military divide became more visible as the mercurial 2nd Army Commander, Lt. General Boonsin Padklang, emerged as a prominent nationalist voice. His assertive stance appealed to segments of the Thai public but further complicated the government’s diplomatic messaging. Cambodian social media and state-controlled English-language media waged an intense information campaign, including spreading misleading content, such as false claims of downed Thai F-16 fighter jet and poison gas attacks by Thailand. Thailand struggled to counter it due to slow and fragmented official communication. Analysis by International Institute of Strategic Studies (IISS) suggests internal political instability in Thailand, stronger Cambodian narrative control, and Beijing’s tacit backing for Cambodia all created asymmetries in strategic flexibility.
ASEAN’S Role and International Involvement
The Association of Southeast Asian Nations’ (ASEAN) lack of early warning and preventive diplomacy allowed Thailand-Cambodia tensions to build further. It neither intervened nor voiced concern between February and July 2025, reflecting its tendency towards slow, status quo-oriented conflict management. Historical reliance on bilateral mechanisms like the Joint Boundary Commission, which remained inactive for 13 years, further delayed resolution. However, Malaysia’s proactive mediation and observer efforts as Chair of ASEAN marked a potential shift from this passive approach.
Legal, Humanitarian, and Military Dimensions
A key point of divergence concerns international adjudication. Thailand insists on resolving the dispute bilaterally through the Joint Boundary Commission which was established 25 years ago, rejecting outside intervention. On the contrary, Cambodia has sought to internationalise the dispute. It referred the escalating conflict to the UN Security Council in July 2025, and has requested a ruling from ICJ on the border’s demarcation. This has presented Thailand with a dilemma. This recalls Thailand’s traumatic experience with the ICJ in 1962, which it views as a moment of national humiliation. This historical sensitivity makes it politically impossible for Thai leaders to accept renewed ICJ involvement.
Thailand has tried to shift the narrative by highlighting Cambodia’s alleged new use of landmines. Diplomatic missions and journalists were taken to the border areas to view munitions allegedly recovered from Cambodian positions, including Russian-made PMN-2 mines, which contain a large quantity of explosives—enough to cause severe limb damage and are difficult to deactivate. Some of these appeared new. Thailand is now calling on other Ottawa Convention signatories to take action against Cambodia and is urging donor countries to suspend demining aid to Phnom Penh.
Cambodia has responded by accusing Thailand of using cluster munitions and white phosphorus shells. Although these are not banned under international law, their use raises humanitarian concerns. Cambodia has also circulated images of damage to the Preah Vihear temple allegedly caused by Thai shelling, which Thailand has denied. These mutual accusations have deepened mistrust and made diplomatic progress difficult.
Regional and Economic Implications
The conflict had immediate social and economic repercussions. Cross-border migration has been severely affected, with hundreds of thousands of Cambodian migrant workers leaving Thailand. This exodus threatens Cambodia’s already fragile economy, which relies heavily on remittances. Nationalist sentiment on both sides has surged, with the border being portrayed as a sacred line central to national identity. Neither government could afford to be seen as conceding territory at the moment, making compromise politically costly.
Hun Sen and Hun Manet have strengthened their domestic standing by presenting themselves as protectors of Cambodian soil. In contrast, Thailand’s fragmented leadership has struggled to manage both the military and public opinion effectively. The conflict has further drawn international attention due to its potential to destabilise a critical region of mainland Southeast Asia. The involvement of international institutions like the UN and ICJ, along with accusations over banned weapons, has given the conflict a broader diplomatic dimension.
Looking forward
The Thailand-Cambodia border conflict of 2025 is not an isolated episode but a culmination of historical grievances, political rivalries, contested national narratives, and fragile bilateral mechanisms. The combination of colonial-era cartographic disputes, the symbolic significance of ancient temples and contemporary nationalist politics has created a volatile mix. With both sides escalating their accusations and showing little willingness to compromise, the prospects for a quick resolution appear slim. This dispute remains a delicate issue and must be addressed with care and in line with international law. Sustainable peace would require political stability in Thailand, renewed bilateral engagement and a carefully designed international mediation that takes into account deep-seated historical sensitivities. Until then, the border would remain as a fault line in Southeast Asia.
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