Tensions between Thailand and Cambodia, particularly along their shared border, have flared up repeatedly over the decades.
While relations between the two Southeast Asian neighbours have been fairly peaceful for a while, historical grievances, national identity, and disputed territory have continued to simmer beneath the surface, and in late July 2025, tensions boiled over into some of the most violent clashes seen in years.
Heavy shelling, rocket fire, and airstrikes – including Thai F‑16 jets – erupted across multiple points along the border, with reports also emerging of cluster munitions being used. The violence left at least 43 people dead, including civilians and soldiers, and forced hundreds of thousands to flee. Critical infrastructure, including temples, hospitals, and schools, was caught in the crossfire.
By early August, a tentative ceasefire brokered by ASEAN in Malaysia helped pause the immediate violence. Still, mistrust, nationalistic rhetoric, and disinformation on social media continue to strain public perception and stall meaningful reconciliation.
In this post, I’ll look at the historical context behind these tensions, and the reasons for periodic flare-ups, especially surrounding the Preah Vihear Temple.
Which Border Areas Are Disputed?
Thailand and Cambodia share a 803-kilometre (499-mile) land border. Most of this is undisputed. However, the most contentious area lies in the northern section, specifically around the Preah Vihear Temple (known as Phra Viharn in Thai), located atop a cliff in the Dangrek Mountains.
The core dispute is not over the temple itself (which was awarded to Cambodia by an international court), but over a 4.6-square-kilometre tract of land surrounding it. This zone has been the site of military standoffs and occasional skirmishes, most notably in the late 2000s and early 2010s.
Historical Background: Colonialism and Conflicting Maps
The roots of the dispute lie in the colonial era, particularly during France’s control of Cambodia and parts of modern-day Laos and Vietnam (then French Indochina).
In 1904, Siam (modern-day Thailand) and France agreed to define the border along the watershed of the Dangrek Mountains.
In 1907, French cartographers produced a map that placed Preah Vihear Temple on the Cambodian side, despite it technically lying on the Thai side of the watershed.
Thailand accepted the map initially, but disputes arose as the temple’s significance grew over time.
In 1962, the International Court of Justice (ICJ) ruled in favour of Cambodia, stating that Thailand had accepted the map and was bound by it. The court ordered Thailand to withdraw from the temple area and return any artefacts.
This ruling deeply angered many Thais and continues to stir nationalist sentiment.
Modern Tensions and Armed Clashes
Despite the 1962 ICJ ruling and its 2013 clarification, the border surrounding Preah Vihear Temple – and other sections of the Thai-Cambodian frontier – remained poorly demarcated for decades. This ambiguity has allowed tensions to resurface repeatedly.
Here’s how the conflict has reignited over time:
1. 2008 UNESCO Listing
In 2008, UNESCO listed Preah Vihear Temple as a World Heritage Site under Cambodian management. Thailand strongly opposed this move, arguing that it implied Cambodian sovereignty over the surrounding disputed land. The decision ignited a surge of nationalist outrage in Thailand, particularly from the People’s Alliance for Democracy (PAD), or Yellow Shirts, who framed it as a betrayal of Thai territory.
2. Military Build-Up and Clashes (2008–2011)
- In the wake of the UNESCO decision, both sides began to increase their military presence near the temple.
- October 2008 – Thai and Cambodian troops exchanged fire near the temple, resulting in two deaths.
- February & April 2011 – A series of heavy exchanges occurred, involving artillery and rocket fire. Fighting damaged the temple complex and displaced thousands of civilians on both sides of the border.
3. Post-2011 Incidents and Skirmishes
While tensions cooled after the 2011 clashes, low-level incidents and provocations continued sporadically:
- 2013 – The ICJ clarified that Cambodia had sovereignty over the temple itself and that Thailand must withdraw troops from the “vicinity.” However, the court did not define the exact boundaries of the disputed 4.6 km² area, leaving key ambiguities unresolved.
- 2015–2020 – Border patrols from both sides occasionally reported stand-offs, but diplomatic channels managed to keep the situation from escalating.
- 2018 – A minor standoff occurred when Thai engineers began roadwork near the border, prompting Cambodia to send a protest note. The situation de-escalated after talks.
4. The 2025 Clashes: Worst Violence in Over a Decade
In late July 2025, the dispute exploded into the most serious violence since 2011. Fighting erupted near the Ta Muen Thom and Ta Moan Thom temples, escalating rapidly across multiple border zones.
- Thai air force F-16 fighter jets carried out airstrikes against Cambodian positions.
- Cambodia accused Thailand of using cluster munitions and targeting cultural heritage sites, including areas near Preah Vihear.
- Artillery and rocket fire hit civilian areas in Sisaket and Surin provinces, killing over 40 people, including children.
- Thousands were displaced on both sides; martial law was declared in Thai border provinces.
- Diplomatic ties were suspended as both countries withdrew ambassadors.
A fragile ceasefire brokered by ASEAN was reached in early August, but both militaries remain on alert. The risk of renewed conflict remains high amid mutual distrust and heightened nationalism.
5. Nationalist Politics and Domestic Agendas
Throughout the years, border disputes have often been used by political actors in both countries to serve domestic agendas:
In Thailand, nationalist factions have frequently used border issues to criticise governments seen as too conciliatory toward Cambodia.
In Cambodia, Prime Minister Hun Sen has repeatedly invoked Thai encroachment to bolster patriotic sentiment and consolidate power during moments of domestic pressure.
Why Do Tensions Still Linger?
Despite the legal rulings and a relative peace in recent years, the potential for future flare-ups remains:
- Nationalism: The issue is deeply tied to national identity and pride in both countries.
- Unclear Border Demarcation: Despite ICJ rulings, the full demarcation of the border has yet to be completed or accepted by both sides.
- Military Presence: Small military outposts still exist on both sides of the disputed zone, raising the risk of accidental conflict.
- Political Opportunism: In times of internal strife, politicians may inflame border issues to deflect attention or rally nationalist support.
- Cultural Importance: Preah Vihear is not just a monument, it is a symbol of heritage and legitimacy for both Cambodians and Thais.
Efforts at Peace and Cooperation
There have also been positive steps:
- Joint border commissions have been established to work on demarcation and de-escalation.
- Economic cooperation and cross-border trade continue to grow in other parts of the border, especially around Aranyaprathet–Poipet.
- Both countries have at times agreed to avoid confrontation and reduce troop presence.
However, real resolution likely depends on long-term political stability in both countries and a commitment to shared cultural stewardship over contested heritage sites.
Final Thoughts
The Thai-Cambodian border dispute, particularly around Preah Vihear, is a classic example of how colonial-era borders, national pride, and political agendas can collide to fuel modern conflict. While the region has long been a diplomatic flashpoint, the 2025 clashes marked the first time that expats living just miles from the border experienced real danger, with homes, schools, and infrastructure coming under threat. For many, the risk to life became startlingly real.
That said, this level of violence is highly unusual. Both Thailand and Cambodia depend heavily on tourism and cross-border trade, and have strong incentives to prevent full-scale conflict. With broader economic and regional relationships at stake, it’s likely that diplomacy will prevail over escalation, though tensions will continue to simmer beneath the surface.
For travellers or expats, the vast majority of the border remains calm, and such events are still rare. But understanding the deep historical roots and recurring political motives behind these flare-ups helps make sense of the headlines, and reminds us how easily the past can ignite the present.
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