The July 2025 hostilities between Cambodia and Thailand stemmed from a decades-long border dispute around the Preah Vihear and Ta Muen Thom temples, only partially settled by International Court of Justice rulings and preceded by lethal clashes in 2011. Thailand’s internal instability, marked by recurrent coups, contested elections, dissolution of a political party, and a continuing non-international armed conflict (NIAC) with the Barisan Revolusi Nasional (BRN), as well as risks of spillover from conflicts in Myanmar, formed the wider context. Rising bilateral tensions over maritime delimitation and border incidents culminated in late July 2025 hostilities at multiple sites, causing dozens of deaths and mass displacement, followed by a Malaysia brokered ceasefire in August that brought only temporary de-escalation. Through autumn 2025, renewed skirmishes and border incidents led to further escalation in early December, until a new ceasefire on 27 December 2025 and the eventual release of Cambodian prisoners of war.
Classifications and Parties to the Conflicts
- International armed conflict between Cambodia and Thailand
- Non-international armed conflict between Thailand and Barisan Revolusi Nasional (BRN)
In the Cambodia-Thailand hostilities, both States reported civilian casualties and mass displacement, and accused each other of attacks on civilian areas, including air and heavy weapon strikes in and around populated border regions. Those attacks raised concerns under IHL rules on distinction, proportionality, and precautions in attack. Thailand also alleged that Cambodia newly emplaced anti-personnel mines in breach of the Anti-Personnel Mine Ban Convention, while Thailand acknowledged using cluster munitions against military objectives, whose effects pose significant risks to civilians. An incident of conflict-related sexual violence was also reported. Renewed hostilities in December 2025 triggered large-scale cross-border displacement, and delay in repatriating Cambodian prisoners of war. In southern Thailand, the NIAC with BRN was marked by attacks causing civilian casualties, torture, and arbitrary detention by security forces, and the recruitment of children.
Historical Background
Origins
The July 2025 fighting between Cambodia and Thailand arose from a decades-long border dispute along their shared frontier of more than 800 kilometres, with particular contestation around the Prasat Ta Muen Thom and Preah Vihear temples in the Dângrêk mountains. The border was drawn by French cartographers in 1904 and 1907.
Preah Vihear adjudication
After Cambodia’s independence in 1953, Thai troops occupied the Preah Vihear temple, prompting proceedings before the International Court of Justice. In 1962, the Court affirmed Cambodian sovereignty over the temple on the basis that Thailand had accepted Cambodian control for decades, while leaving the status of surrounding areas unresolved. A further judgment in 2013 reaffirmed that the temple and only the immediately surrounding area fall within Cambodia.
2011 renewed border-clashes
In 2011, clashes between Cambodian and Thai forces in the vicinity of Preah Vihear resulted in at least sixteen deaths. A period of relative calm then prevailed until 2025.
Internal context in Thailand
Thailand has experienced recurrent military coups since the transition of the Thai Kingdom into a constitutional monarchy in 1932, resulting in political instability. In southern provinces, a non-international armed conflict (NIAC) between Thai forces and the Barisan Revolusi Nasional (BRN) has been ongoing since 2004. The conflict has been marked by insurgent attacks on civilians and widespread torture by State authorities. Attempts at dialogue have produced limited ceasefires, with talks repeatedly undermined by coups and stalled on self-determination for Malay Muslims.
Key Developments (2023–2025)
During the reporting period, the situation saw several major developments:
- Formation of a new government after May 2023 elections: After the May 2023 elections, the Move Forward Party (MFP) won but its leader – Pita Limjaroenrat – failed to secure Thai parliamentary support to form a government. Ensuing disputes centered on his pledge to reform the lèse majesté offence, as well as allegations that his shareholding in a defunct broadcaster breached election laws. Parliamentary and judicial steps to dismiss his candidacy for prime minister, combined with his temporary suspension from his parliamentary duties, triggered demonstrations in Bangkok. In the aftermath of Pita’s suspension, the Pheu Thai Party (PTP) left the MPF-led coalition, nominated Srettha Thavisin, aligned with pro-military coalition, and formed a new government in August 2023 endorsed by the King.
- Thaksin Shinawatra’s return to Thailand: After Srettha was elected Prime Minister, the party de facto leader and former Thai Prime Minister (2001–06), Thaksin Shinawatra, returned from long exile. Upon his return, he was arrested, having previously been sentenced in absentia to eight years in prison. He subsequently received royal pardons and sentence reductions, served his sentence under hospital supervision, and was then released on parole. Later, renewed charges were dismissed, and separate allegations of political interference were rejected.
- Impacts of armed conflicts in Myanmar: Thai nationals, mostly persons coerced into scam operations, were evacuated from Myanmar to China amid intensified fighting. Escalation around Myawaddy (in southern Myanmar) prompted Thailand to reinforce border security and issue directives regarding airspace incursions, while facing important cross-border population movements after signaling readiness to receive large numbers of refugees. A United Nations (UN) report linked Thai financial institutions to Myanmar arms acquisitions, triggering parliamentary scrutiny and the establishment of a governmental task force. The period also saw shooting incident involving two Thai fishing vessels and Myanmar’s navy.
- Dissolution of Move Forward Party: While Pita was cleared in election laws case, the party’s effort to amend the lèse majesté law was found unconstitutional. A sequence of petitions culminated in dissolution of MFP, long bans for MFP executives, international criticism, the creation of a successor party, and pending proceedings against former MFP Members of Parlement (MPs).
- Removal of Prime Minister Srettha Thavisin and election of Paetongtarn Shinawatra: Srettha was removed from office for ethics violations. Paetongtarn Shinawatra, a party member of the PTP and the daughter of Thaksin Shinawatra, formed a cabinet, faced scrutiny for installing two advisers with criminal records and attempts to dissolve her party, and survived a no-confidence vote.
- Peace dialogue between Thailand and BRN: Talks under Malaysian facilitation resumed intermittently, struggling over leadership and self-determination. Following BRN’s criticisms and warnings to the newly appointed government for not selecting a new head for peace talks, the government unilaterally reduced military operations. It did not, though, respond to BRN’s ceasefire proposal, and the violence continued. Following the election of Anutin Charnvirakul as prime minister in September 2025, talks restarted under new negotiators in November 2025.
- Build-up of tensions between Thailand and Cambodia and stepping up of border patrols along Tai-Lao border: In November 2024, political unrest following plan to reopen discussions on delimitation of a maritime aera in the Gulf of Thailand based on a 2001 Memorandum of Understanding (MoU) overlapped with long-standing border frictions. As a result, tensions between Cambodia and Thailand along the shared border rose over the following months and included confrontations at Ta Muen Thom temple in February 2025. In parallel, subsequently to heavy clashes between Lao army and Hmong militants close to Thai border in early May 2025, Thailand intensified border and naval patrols.
- Political crisis in Thailand over handling of conflict with Cambodia: The subsequent leak by Cambodian high official Hun Sen of his call with Thailand’s Prime Minister, Paetongtarn Shinawatra, on 18 June 2025 intensified political unrest, raised concerns over a possible coup, and prompted protests in Thailand. On 1 July 2025, Paetongtarn was suspended and later removed. On 5 September 2025, Anutin Charnvirakul of the Bhumjaithai Party was elected Thailand’s new prime minister, announcing plans to dissolve parliament and pursue constitutional change.
- Renewed hostilities in 2025: Following a period of relative calm, a skirmish between Cambodian and Thai soldiers in Preah Vihear province on 28 May 2025 killed one Cambodian soldier. Although talks were held, several months of heightened tensions between the two States resulted in renewed skirmishes occurring at Ta Mone Thom temple between Thai and Cambodian soldiers on 13 and 15 July 2025. In reaction to landmine detonations in a disputed border area on 16 and 23 July 2025, and while both sides blamed each other for initiating the fighting, hostilities escalated. The fighting spread to around a dozen border sites between 24 and 28 July 2025, killing at least 48 people and displacing more than 300,000 civilians.
- Attempted peace deals/ceasefire agreements between Thailand and Cambodia: A relative calm returned in August 2025 due to a Malaysia-brokered ceasefire arrangements supported by regional mechanisms and proposed monitoring. A new agreement between the two militaries in early September 2025 seemed to pave the way for a period of de-escalation. But clashes between Thai forces and Cambodian civilians on 17 September resulted in dozens of injuries and renewing tensions between both States. Through the autumn of 2025, skirmishes, accusations of recent laying of landmines, delay in the release of Cambodian soldiers, evictions in border areas, and accusation of attacks against Cambodian migrants undermined de-escalation efforts. In November 2025, Thailand suspended the ‘peace deal’ and hostilities escalated again in early December until the signature of ceasefire agreement on 27 December 2025. Despite allegations by the Thai military of ceasefire violations by Cambodian troops, Cambodian prisoners of war were eventually released.
International Armed Conflict
Cambodia vs Thailand
An international armed conflict (IAC) arises when States resort to significant armed force against one another. The brief exchange of fire between Cambodian and Thai forces near Chong Bok on 28 May 2025 did not, however, reach the requisite threshold. Thai authorities indicated that neither States intended to open fire, and the incident was framed as a mistake amid rising tensions and further skirmishes in June and July. By contrast, on 24 July 2025, significant armed force was used following earlier landmine incidents, amid contested allegations regarding the initiation of fighting, triggering an IAC. The confrontation rapidly escalated into reciprocal strikes on military bases, including rockets and air operations, and caused significant casualties and large-scale displacement. Although ceasefire arrangements were concluded after several days, the conflict continued in the absence of a definitive closure of military operations. Heavy fighting erupted again in early December 2025 before a further ceasefire was signed later that month, which appears to have brought the conflict to an end.
Non-International Armed Conflict
Thailand vs the Barisan Revolusi Nasional (BRN)
The conflict between Thailand and the BRN is rooted in the 1909 border arrangement that separated ethnic Malay Muslims across Thailand and Malaysia, and it has remained largely ethnically motivated, with the BRN presenting itself as representing Malay Muslim interests and pursuing independence from Thailand while benefiting from substantial local support. The non-international armed conflict (NIAC) in Narathiwat, Pattani, and Yala (in southern Thailand) has been ongoing since at least 2004, with a brief lull linked to a unilateral COVID-related ceasefire, and it continued throughout the reporting period. In terms of intensity, violence persisted over time and increased in frequency in 2025, with the BRN relying notably on improvised explosive devices and employing guerrilla tactics, assassinations, car bombings and ambushes. Increasingly coordinated attacks, cross-border operational patterns and training aimed at targeting Thai armed forces were also reported. Regarding organization, despite its structure remaining secretive, the BRN has political and military wings, a ruling council and decentralized local cells, supported by disciplinary rules and consolidated public messaging. It also has funding streams through membership fees and business activities, and has been involved in humanitarian commitments and peace talks, notwithstanding recurring internal tensions. The BRN therefore remained sufficiently organized.
Parties to the Conflict(s)
State Parties
- Cambodia
- Thailand
Non-State Parties
- Barisan Revolusi Nasional (BRN)
ATTACKS ON CIVILIANS
In the Cambodia–Thailand hostilities, both States reported civilian casualties and mass displacement and alleged that the adversary conducted attacks affecting civilian areas. Thailand also accused Cambodia of recently emplacing anti-personnel mines in breach of the Anti-Personnel Mine Ban Convention, while Cambodia accused Thailand of using cluster munitions, which Thailand acknowledged using against military objectives. Separately, BRN attacks in southern Thailand reportedly caused civilian deaths and injuries, including harm to children.
Customary IHL prohibits directing attacks against civilians and indiscriminate attacks, and requires compliance with the principles of proportionality and precautions. In the Cambodia-Thailand hostilities, Thailand claimed that in late July 2025 Cambodian forces launched indiscriminate attacks across four Thai provinces, striking civilian infrastructure, including a hospital and a school, and causing civilian deaths and injuries. During renewed hostilities in December 2025, both States reported civilian casualties. In particular, Thailand stated that Cambodia launched further attacks within civilian areas in Sisaket province, while Cambodia asserted that Thai attacks extended beyond military positions and affected civilian areas in several provinces, causing civilian deaths and injuries. Cambodia further claimed that Thai F-16 aircraft dropped bombs near displacement sites and a school, although this allegation could not be verified. Civilians were reported among the fatalities in Cambodia. Separately, in southern Thailand, Barisan Revolusi Nasional (BRN) attacks in April 2025 caused multiple civilian casualties among Buddhist Thai and Malay Muslim communities, including a shooting of monks and novices and a motorcycle bomb detonated as a vehicle carrying students from Quran study passed, wounding several children.
ATTACKS ON CIVILIAN INFRASTRUCTURE
Airstrikes and heavy weapons use in and around populated areas raised concerns under IHL and might amount to indiscriminate attacks.
Attacks on Populated Areas
Airstrikes and the use of heavy weapons in and around populated areas, including around villages and cultural sites, raised serious concerns for civilian protection. In July 2025, the Royal Cambodian Armed Forces fired unguided Grad rockets into Thai border provinces, a method of area attack not designed to strike specific targets, which made civilian harm particularly likely and suggested an indiscriminate attack. Thailand further alleged that Cambodia subsequently launched attacks in civilian areas of Sisaket province in December 2025 and denounced the conduct as ‘cruel and inhumane’.
VIOLATIONS AGAINST PERSONS IN THE HANDS OF THE ENEMY
In southern Thailand, the NIAC was marked by a killing of a human rights defender, reported torture of ethnic Malay Muslims in custody, and detention of suspected BRN members under emergency powers without effective judicial oversight. BRN reportedly recruited children, including under fifteen. In the Cambodia-Thailand hostilities, delay in repatriation of Cambodian prisoners were reported. Sexual violence was also alleged against Thai soldiers.
Murder of Civilians
In late June 2024, in Pattani province, unidentified gunmen shot dead a prominent human rights defender who assisted ethnic Malay Muslim victims of arbitrary arrest and torture by Thai security forces. No progress in investigating his killing has been reported.