The Thai government should resume negotiations with Cambodia to resolve maritime disputes and move towards jointly developing hydrocarbon resources in the overlapping claims areas (OCA) in the Gulf of Thailand, according to a recent study by the Senate’s Military and Security Committee.
The report is a shot in the arm for the Pheu Thai-led coalition government that has long held this position.
Though right-wing nationalist groups are opposed to it, the committee cited in its study that the controversial Memorandum of Understanding (MOU) signed in 2001 would be a useful instrument for settlement of the dispute and joint development of the resources.
“The 2001 MOU is beneficial in terms of resolving the overlapping continental shelf claims, developing the area and maintaining international relations. Therefore, it is appropriate to retain the 2001 MOU, as it already holds the status of a treaty and can serve as a basis for future negotiations to safeguard national interests,” the study says.
Termination of the 2001 MOU could result in increased tensions and negatively affect security cooperation—particularly in border areas—as well as economic and trade relations between the two countries, the study warns, adding this could also undermine mutual trust in future border negotiations.
“Without the framework provided by the 2001 MOU, there would be no common platform or rules for conducting joint surveys or demarcating the boundary. This could prolong the maritime disputes or escalate them into future conflicts,” it says.
The Pheu Thai-led government has announced many times over the past two years its plans to resume negotiations, solve the maritime disputes and jointly develop the oil and gas reserves in the OCA, but it is yet to act due to opposition from nationalist groups.
The Senate’s committee completed and proposed the report for consideration of the Senate president in late March.
While the tone of the overall report backs negotiations under the 2001 MOU framework, Prime Minister Paetongtarn Shinawatra and her cabinet have not shown confidence to walk the talk.
Paetongtarn’s official visit to Cambodia in late April omitted the sensitive OCA issue from her agenda following opposition from a right-wing group led by the Student and People's Network for Thailand Reform and former yellow shirts, who have ratcheted up their rhetoric on loss of territory and conflict of interest.
The nationalist groups have threatened to call street protests to bring down the government if the Paetongtarn administration resumed talks with Cambodia about the OCA and national resources in the Thai sea. The groups had successfully carried out a campaign in the Preah Vihear temple case over a decade ago.
Koh Kut belongs to Thailand
The Senate’s study confirmed that the island of Koh Kut belongs to Thailand de facto and de jure.
One of the key legal documents it cites is the Franco-Siamese Treaty signed on March 23, 1907 whose Article 2 clearly states that "the French government agrees to return the territories of Dan Sai and Trat, along with all islands south of Laem Sing, including Koh Kut, to Siam...”
Additional evidence includes a Cambodian decree declaring its maritime baseline, which contains a map labeling “Koh Kut” beneath the word “Siam”, indicating clear recognition of Thailand’s sovereignty over the island, the report says.
Thailand reinforced its sovereignty by installing a lighthouse on Koh Kut on December 19, 1974, as officially announced by the Navy’s Hydrographic Department, the report says. This action was documented in British Admiralty Chart No. 3967, which marked the lighthouse’s location, further affirming Thailand’s jurisdiction over the island.
While there has been no official claim from the government in Phnom Penh over Koh Kut, the island is becoming a hot-button issue for Cambodian Prime Minister Hun Manet as well.
The Cambodian opposition has demanded that their government officially file a claim for sovereignty over Koh Kut with the International Court of Justice, which had ruled in favor of Phnom Penh in the Preah Vihear case.
Heavy cost of unexplored natural gas
The continental shelves in the gulf claimed by Thailand and Cambodia since the 1970s span approximately 26,000 square kilometers, with Koh Kut located at its northern edge.
Studies suggest this area holds significant energy resources, including an estimated 11 trillion cubic feet of natural gas and 300–500 million barrels of crude oil, with a combined economic value of around US$300 billion.
However, due to the unresolved maritime boundary, full-scale exploration has not taken place.
The importance of these resources has grown as Thailand’s existing gas fields in the Gulf are depleting, forcing the country to rely increasingly on costly liquefied natural gas (LNG) imports, the Senate’s report says.
Moreover, the OCA lies along the same geological trend as the Erawan gas field—one of Thailand’s key energy sources—making development in this area essential for reducing import dependence and enhancing national energy security.
From Cambodia’s standpoint, exploiting the OCA’s resources could provide a big boost to its economy, as its oil and gas sector remains at an early stage of development.
“Given these strategic and economic imperatives, Thailand should carefully consider how to best utilize the OCA’s energy and natural resources to maximize national benefit,” it said.
The truth about border tensions
Defense Minister Phumtham Wechayachai confirmed reports widely spread in social media earlier that Cambodian troops had encroached on disputed border areas in Northeastern Ubon Ratchathani province for quite some time, but subsequently withdrew following a request from the Thai authorities.
Pictures in social media showed trenches were dug in the area adjacent to hill 475 of the Chok Bok border pass, in Ubon Ratchathani’s Nam Yuen district, where the demarcation of land boundary has not been completed.
Phumtham played down the conflict, explaining that the incident stemmed from a lack of prior communication, which had led to actions exceeding the agreed boundary lines.
“Once addressed, a request was made for them to withdraw, as the actions were beyond what had been discussed at higher levels,” he said. “Cambodia complied and pulled back, leaving only the trench visible.”
The misunderstanding may have been due to Cambodia following its previous claim line, while discussions had outlined the need for separation of claims, he said.
Thai nationalists have used social media to precipitate border tensions with Cambodia over the past few months after a verbal altercation between Thai and Cambodian soldiers at the Ta Moan Thom Hindu sanctuary in the northeastern Surin province in February, as well as a fire incident at the Trimuk Pavilion near the border junction in Ubon Ratchathani in March.
The pro-military Phalang Pracharat Party demanded that Prime Minister Paetongtarn and her deputy Phumtham adopt a tough stance against Cambodia. They also reiterated Thai sovereignty over the sandstone temples located in the disputed border areas.
Striking a discordant note, the Cambodian Defense Ministry issued a statement on May 12 that the recent meeting of the General Border Committee co-chaired by minister Tea Seiha and his Thai counterpart Phumtham in Bangkok agreed to continue their joint presence at the Ta Moan Temple, where each side would maintain five soldiers.
“There was no discussion of troop withdrawal from the temple. Instead, both sides pledged to maintain regular communication and coordination to prevent misunderstandings or potential clashes,” the statement said. It contradicted Phumtham’s remarks to Thai media that both sides had agreed to withdraw all troops from the Hindu temple.
