On 5 May 2026, Thailand announced a unilateral termination of its Memorandum of Understanding dated 18 June 2001 (“Agreement”) with Cambodia pertaining to their joint exploration rights in the area of their overlapping Maritime Claims to the Continental Shelf.
The 25-year-old Agreement sought to accelerate negotiations of a Joint Development Treaty to streamline joint exploitation of the hydrocarbon resources in the territorial sea, continental shelf and exclusive economic zone in the Gulf of Thailand. Thailand’s Prime Minister Anutin Charnvirakul attributed this impending termination to lack of progress in achieving the objectives of the Agreement, stating that, “[c]ancelling the deal is not related to the border conflict with Cambodia, but part of my policy. It has been 25 years and there has been no progress”.
Cambodia has expressed regret over the severed maritime pact. Cambodia’s Foreign Minister Prak Sokhonn remarked that the State has no option but to settle the boundary dispute with Thailand legally under the 1982 United Nations Convention on the Law of the Sea (“UNCLOS”). He stated, “Cambodia’s decision to pursue compulsory conciliation under UNCLOS reaffirms its commitment to resolving maritime disputes peacefully and in accordance with international law”.
Thailand and Cambodia have both excluded from the compulsory and binding dispute settlement mechanism in Part XV of UNCLOS, any disputes concerning the interpretation or application of Articles 15, 74 and 83 relating to sea boundary delimitations or those involving historic bays or titles. However, pursuant to Article 298, such exclusion is subject to the proviso that, if disputing parties fail to reach an agreement within a reasonable period of time, one of them can oblige the other to submit the dispute to conciliation under Annex V, section 2. This is what Cambodia has now done.
As a context to this recent development, in relation to their land boundary both countries engaged in armed hostilities in 2025 over competing territorial claims. Cambodia officially approached the International Court of Justice to resolve its enduring border dispute with Thailand.
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