The Cambodia-Thailand Border Conflict Explained: A Fragile Relationship

Amidst several high-profile global conflicts, late July saw yet another spark with escalations between Cambodia and Thailand. Triggering fatalities, mass evacuations and a political crisis, danger remains in sight as repeated cross-border accusations have been voiced in September. But what exactly has happened? And what are the likely scenarios moving forward? 

Border Clashes – A Common Occurrence

Sharing an 817 kilometer (508 mile) border, disagreements between Thailand and Cambodia is not an unfamiliar event. In fact, clashes can be found dating as far back as the early days of Cambodian independence in 1953. Yet, tensions have intensified in recent decades. In 2008, the Preah Vihear temple – located by the border – was established as a UNESCO World Heritage Site of Cambodia. The temple has been claimed by both countries but has twice been ruled by the International Court of Justice (ICJ) as rightfully part of Cambodia, to the disapproval of Thailand. 

Preah Vihear, the contested temple along the Cambodia-Thailand border. Photo: PsamatheM - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=170517476

The conflict has since expanded to other temples along the geographical border, where Cambodia has claimed that the Thai military has crossed territorial boundaries on multiple occasions Between 2008 and 2011, 19 Cambodian soldiers and 16 Thai soldiers were killed in skirmishes before an agreement put a temporary end to the dispute. 

Renewed Tensions and Conflict in 2025

Previous agreements between the two Association of Southeast Asian Nations (ASEAN) states have not erased all disputes. The often heavy deployment of soldiers on each side of the border reflects anything but a harmonious relationship. On May 28, 2025, renewed skirmishes led to the death of a Cambodian soldier, reigniting the conflict. 

Both countries immediately stated their wishes to avoid an escalation, yet branded the other party as the aggressor. Cambodia claimed Thai soldiers had opened fire across the border at a Cambodian army base, while Thailand stated Cambodia shot first when refusing to back away from a disputed border zone. When meetings between respective parties left border disputes unresolved, reciprocal fruit import tariffs and border checkpoint closures followed suit, intensifying an already tense situation. 

By July 24, the diplomatic dispute spilled over into direct military confrontation along the border, with another instance of conflicting reports over which side was the aggressor. The following four days saw military intrusions into respective countries, including the usage of Cambodian BM-21 Grad rockets and Thai F16 fighters, causing large-scale evacuations of civilians and at least tens of soldiers and civilian fatalities on both sides. 

Cambodian armed forces in the border area, where contended temples are located

A Fragile Ceasefire

While the exact number of fatalities remain contested, the events undoubtedly resulted in the largest ever clashes along the Thailand-Cambodian border. The escalations saw widespread but carefully worded condemnations from global and regional actors, including the US, the EU, China, and ASEAN, all avoiding attaching blame to a specific country. 

Despite reportedly opposing third-party mediation at the early stages of the conflict, threats by US President Donald Trump to halt all trade negotiations along with diplomatic efforts by ASEAN Chair Malaysia saw representatives from each country meet on July 28 and agree to a ceasefire. Headed by Malaysian Prime Minister Anwar Ibrahim, both countries agreed to de-escalation, yet reports from the border zone quickly claimed fighting continued. Despite strongly worded accusations directed at each other over the following days, a detailed plan for de-escalation was finalized by August 7, including ASEAN defense deployment teams to monitor the situation on the ground. 

Has the Ceasefire Succeeded?

In short, the ceasefire agreement has successfully de-escalated the conflict. Nonetheless, tensions between the two countries have clearly not evaporated; Thai accusations of Cambodian-planted landmines by the border and civilian protests in Cambodia in the border province of Sa Kaeo highlight a deeper issue. Additionally, Thai Prime Minister Paetongtarn Shinawatra was removed from office on August 29 following a leaked phone call with Cambodian de facto leader Hun Sen. In the call, Paetongtarn was heard calling Hun Sen “uncle” and criticised her own military’s actions in the conflict, leading to domestic protests and her removal by Thailand’s Constitutional Court. 

Paetongtarn Shinawatra, Thailand’s ex-Prime Minister forced out of office

While Thailand is actively battling internally with the aftermath of its political crisis, renewed border escalations have emerged during September and October, where each side has accused the other party of violating the ceasefire. Stemming from Cambodian protestors in the border area, Thai forces have been accused of deploying both tear gas and rubber bullets in response inside Cambodian territories. Yet, Thailand has insisted on Cambodian forces making no effort stopping protestors, and that the incidents in fact had occurred in Thai territory. Clearly, border tensions remain at an extreme.

A Costly Conflict For All, Stirred by Nationalism

From an observer’s standpoint, the conflict lacks a clear winner, while losses have been made on each side. In addition to at least dozens of fatalities for both countries, hundreds of thousands of civilians near the borders have been forced to evacuate. This includes Cambodian workers in Thailand who have returned to their home country following threats of violence amid rising nationalist sentiments. Cambodian migrant workers have provided a vital labour source for Thailand, while an estimated return of 2 million Cambodians threatens worsening existing high unemployment and poverty rates in their home country.

So, if there were no winners, why did the conflict start, escalate and remain largely unresolved? A clear frontrunner among varying explanations is a simple one: nationalist sentiments fueled by social media. A first escalation created pressure on each side to demonstrate strength along the contended border. Misinformation was a common feature in both domestic narratives, leaving even less room for the countries to see past their differences. 

Propaganda and social media attacks has been a strong theme in both countries

Nationalist sentiments help explain the storm brought on Prime Minister Paentongtarn following her leaked phone call. Her limited sympathy with her own country’s cause in a friendly conversation with “enemy” figures deviated from a strong national assertion expected by the domestic audience. Given the authoritarian elements found in each government, nationalist sentiments will likely not disappear in the short-term, leaving the wider conflict unresolved for the foreseeable future.

ASEAN: A Winner or Loser?

Having previously been a largely peaceful region with no interstate warfare between its members, the 2025 Cambodia–Thailand border conflict undoubtedly raises questions on the function and strength of ASEAN, an organization based on respect for sovereignty and peaceful settlements of disputes. This has put strains on an already tense situation for the region already affected by an ongoing civil war in Myanmar and recent large-scale protests in Indonesia. 

Yet, one could also see the outcome as a testament to ASEAN’s peace-promoting efforts. With Malaysian Prime Minister Dato' Seri Anwar Ibrahim acting as present Chairman of ASEAN, his successful mediation efforts should not go unnoticed, while ASEAN deployment teams help prevent renewed flare-ups. In this sense, without ASEAN’s existence, the risks for escalation into an outright war would undoubtedly have been higher – a scenario which could have devastated the wider region.

Barbed wires placed by Thai armed forces to prevent movement of Cambodian protestors. Will separation ease tensions?

The Role of Donald Trump

In addition to Malaysia’s major soft power success, President Trump’s involvement undoubtedly played an important role in quickly ending the violence. Through his aggressive bargaining tactics with two export-heavy economies, his threat to halt trade negotiations helped both countries mutually see the destructive ends of continuing the conflict. With Cambodia having nominated Trump for the Nobel Peace Prize, it remains to be seen whether he can make further efforts limiting the long-lasting tensions.

A Battle of Contending Forces

A heatwave of violence during summer is yet to prove convincing evidence of a chilling fall. Repeated cross-national accusations and limited progress since ceasefire efforts in July and August means the Cambodia-Thailand border conflict continues needing hefty attention. The mutually destructive effects of conflict will be challenged by a need for respective governments to display strength in the wake of nationalistic sentiments among domestic audiences. Only time will tell which force proves to be the strongest.