Cambodia–Thailand oil wealth trapped at sea

Cambodia and Thailand are sitting on a fortune in untapped oil and gas, yet decades of political mistrust have left the reserves locked beneath the Gulf of Thailand. The contested zone, known as the Overlapping Claims Area, is thought to contain 12 trillion cubic feet of natural gas and 700 million barrels of oil—resources valued at around $300 billion.

The dispute flared in May when Thailand cancelled the 2001 memorandum of understanding, the only framework for joint talks. Cambodia responded by invoking a rare UN conciliation process under the Law of the Sea treaty, hoping to force Bangkok back to negotiations. It is only the second time such a mechanism has been used, the first being Timor‑Leste’s case against Australia in 2016.

Phnom Penh argues the stakes are regional. “Any potential discovery from this area would definitely provide economic and energy benefits to Thailand, Cambodia and the ASEAN region at large,” said Cambodia’s Minister of Mines and Energy, Rottanak Keo. He stressed that Cambodia has invested heavily for 25 years to resolve the issue peacefully.

Thailand insists the framework had failed to deliver progress and now wants to settle the maritime boundary before discussing revenue sharing. The move followed armed clashes along the land border that displaced hundreds of thousands of civilians, fuelling nationalist sentiment in Bangkok.

For Cambodia, the longer talks stall, the greater the risk that international energy companies will walk away. ConocoPhillips, TotalEnergies and China’s CNOOC all hold concessions in the disputed zone but have frozen investment pending clarity. With global capital shifting towards renewables, Phnom Penh fears the opportunity could slip away.

The economic case is compelling: ASEAN imports more than 80 per cent of its oil and gas, much of it through the vulnerable Strait of Hormuz. Unlocking the Gulf’s reserves could ease that dependence. Yet for now, billions in potential wealth remain trapped underwater, hostage to politics.

-2026-07-08