Thailand to tear up MOU 44 as Hun Sen blocks border reset

Thailand is preparing to scrap MOU 44 with Cambodia, in a major policy shift that threatens to reopen one of the most sensitive disputes along the Thai-Cambodian border, from overlapping maritime claims and undersea resources to land control and the unresolved sediment dam issue.

The move is expected to be formally embedded in the new government’s policy statement. According to the political timetable, Prime Minister Anutin Charnvirakul will lead the new Cabinet in taking the oath of office on April 6, 2026. The first Cabinet meeting is due the same day to approve the policy statement for delivery to Parliament, expected on April 9-10.

One of the campaign promises Anutin made during his major rally before the February 8, 2026 election was the cancellation of the Thai-Cambodian MOU 44. That pledge now appears set to be turned into official government policy.

After summoning Defence Minister Lt Gen Adul Boonthamcharoen and Adm Thadawut Thatpitakkul, chief of naval staff, to Bhumjaithai Party headquarters on March 31, Anutin made his position plain.

“I’ve made my decision. For me, that means cancellation. The cancellation of the 2001 MOU will be included in the policy statement to Parliament,” he said.

MOU 44 is an extension of MOU 43, stretching from land boundary marker 73 in Khlong Yai district of Trat to the continental shelf, where resources above ground, underground and beneath the seabed are believed to be at stake. Yet more than 20 years after it was signed, the agreement has produced no breakthrough, largely because Thailand and Cambodia have never agreed on where the maritime boundary should lie.

Although successive Thai and Cambodian governments have tried to push forward negotiations on sharing undersea resources, the effort has never taken concrete shape. The Thai military has consistently insisted that any benefit-sharing must be negotiated alongside maritime boundary demarcation and can never be separated from it.

That position reflects a broader anxiety in Thailand that MOU 44 could one day carry territorial consequences. Critics argue that the document risks being read as Thai acceptance of Cambodia’s so-called Line 266, declared in 1972, which cuts across Koh Kood. They also point out that Cambodia has shown little serious intent over the years to bring the dispute to a final resolution.

Lt Cdr Khunawut Rungrasamee, commander of Marine Battalion 182, which oversees the area around boundary marker 73 in Ban Hat Lek, Khlong Yai district, said the dispute in this sector centres on three key markers. Marker 71 remains in place, while marker 72 has disappeared, prompting the Royal Thai Survey Department to establish two control points for reference.

He said the contested area now covers around 286,098 square metres. The roots of the problem go back to the 1907 Siam-France treaty, under which boundary markers on land were laid down. At the time, the intention was to use the highest point on Koh Kood as a reference, but applying the line rigidly would have split a village in two and created serious administrative complications. As a result, the boundary point was defined in a way intended to preserve workable governance.

Lt Cdr Khunawut said Thai-Cambodian negotiations over the maritime line had continued since the 1970s without agreement, eventually leading to MOU 44.

He also acknowledged that the area remains entangled in another long-running dispute: a sediment-trapping dam built by Cambodia in 1997. Thailand has lodged protests over the structure for years, saying it violates sovereignty and disrupts the local ecosystem. According to Thai authorities, the dam prevents sediment from flowing naturally into Ban Hat Lek, causing Thailand to lose around 3,000 square metres of land, while a casino resort area in Koh Kong has expanded by about 30,000 square metres.

Although Cambodia dismantled part of the dam during an earlier period of clashes, it did not excavate down to the foundation. The Naval Hydrographic Department has said that proper ecological restoration would require dredging three metres below the original crest line all the way to the base over a distance of 240 metres, to allow sediment to flow back into Thailand. Cambodia, however, removed only around 120 metres and stopped short of the lower base. Talks are still needed on what should happen to the remaining section.

There are also reports that, during recent Thai-Cambodian hostilities, business figures in Koh Kong ordered the dam to be removed in line with Thai demands, but the operation was never completed. According to those reports, Hun Sen, president of the Cambodian Senate, learned of the move and reprimanded the commander of Cambodia’s Region 3 forces, who is responsible for the area. The dismantling then stalled.

What stands out is that Cambodia has so far shown little public reaction to Thailand’s plan to revoke MOU 44. One explanation may be that ending the agreement would not materially damage Cambodian interests, given that the past two decades have produced no progress at sea anyway.

MOU 43 is a different matter. Unlike MOU 44, which deals with the maritime dimension, MOU 43 concerns land areas and is regarded as far more useful to Cambodia. Hun Sen is believed to see it as a tool to pressure Thailand into pulling back from all controlled areas after the recent clashes, because it contains a condition requiring both sides to leave disputed territory untouched until the Thai-Cambodian Joint Boundary Commission clarifies the border line.

That is why Hun Sen quickly objected after a Senate committee in Thailand voted in favour of recommending the cancellation of MOU 43.

Anutin has not yet made his final position on that agreement clear. However, he has instructed Foreign Minister Sihasak Phuangketkeow and the military to submit proposals to the government.

The Royal Thai Army had already raised questions over whether MOU 43 remains workable under current conditions, arguing that the environment and strategic context have changed enough that revisions or an entirely new mechanism may now be needed.

A military source said MOU 43 was a useful instrument in principle, but Cambodia had failed to observe it in practice. The source added that recent military operations had already gone beyond its framework, making any withdrawal unrealistic. Instead, the Thai military is holding to the joint agreement signed on December 27, 2025, especially the condition requiring forces to remain in their original positions before the ceasefire.

Along the Thai-Cambodian border, Thai forces are still seen as holding the upper hand on the ground, including in areas covering scam operations inside casino resorts. Those positions could become bargaining chips in future talks with Phnom Penh.

The bigger question now is what strategy the Anutin government will use to force a breakthrough. One possible path would be to rely on international law in place of MOU 44, while pushing ahead with maritime demarcation and tackling the unfinished sediment dam issue at the same time. On land, any future framework to replace or revise MOU 43 would have to reflect the new security realities.

For now, both the land and maritime disputes remain far from settled. Unless Thailand and Cambodia can find common ground, preserve their differences and move forward under a shared mechanism, the border conflict is likely to drag on for years.