Thailand has formally submitted its response to Cambodia’s 2 June notification to enter compulsory conciliation proceedings over their maritime boundary dispute under the 1982 United Nations Convention on the Law of the Sea (UNCLOS), reaffirming its preference for maritime delimitation over joint development. 

The Ministry of Foreign Affairs revealed that Thailand submitted its formal response to Cambodia last Friday (19 June), accepting participation in the UNCLOS conciliation proceedings aiming to resolve their maritime disputes in the Gulf of Thailand, according to the statement.

Thailand informed Cambodia of the appointment of Sihasak Phuangketkeow, Deputy Prime Minister and Foreign Affairs Minister, and Songchai Chaipatiyut, Ambassador to Kuwait, as Agent and Deputy Agent for the conciliation proceedings.

Thailand also appointed its two conciliators: Judge Albert J. Hoffmann of South Africa and Judge Rüdiger Wolfrum of Germany. Both are former Presidents of the International Tribunal for the Law of the Sea and are highly respected in international law.

In accordance with the procedures, the four appointed conciliators, two from each country, will meet within the next 30 days to select the fifth conciliator to serve as Chair of the Conciliation Commission.

In addition, Thailand reaffirmed that the conciliation proceedings will be limited solely to maritime delimitation. 

During the Ministry’s press conference on Monday (22 June), Maratee Nalita Andamo, Deputy Director-General of the Ministry’s Information Department, asserted that the appointed conciliators will not act as lawyers for the appointing countries, but rather neutral experts who will hear from both sides and suggest an amicable solution. 

The Ministry also addressed public concerns, stating that the Commission’s recommendations are not legally binding, and the outcome will not result in either a loser or a winner. 

Both Thailand and Cambodia agreed that 10,000 square kilometres north of latitude 11° North remains to be delimited, while the disputed area south of this was designated as a Joint Development Area (JDA), according to the scrapped maritime MoU.

Regarding the maritime disputes, Thailand reaffirmed the stance it had maintained since the maritime MoU entered into force in 2001. Cambodia prioritised the JDA, where both countries can share the benefits of natural resources, while Thailand prioritised maritime delimitation.

This was the reason the arrangements in the 2001 MoU were an ‘indivisible package’, which required both countries to negotiate on both areas in parallel. Due to their differing stances and domestic politics, the negotiations on the maritime boundary under the 2001 MoU were stalled.  

The Ministry’s representative remarked that Thailand will continue the same position in the conciliation proceedings, reaffirming that maritime delimitation should be addressed before any discussion of joint development, and if possible, that no overlapping area should remain.

The Ministry stated that joint development may be an alternative only in areas where both sides’ legal claims carry comparable weight and maritime delimitation cannot be fully achieved. However, joint development should not be treated as a primary objective for the conciliation process.

After the Conciliation Commission issues its report, both countries will have to enter into a new bilateral agreement. In addition, the representative noted that the bilateral agreement will have to be approved by the National Assembly, as it is considered a treaty that leads to a change to Thai territories according to Section 178 of the Thai Constitution. 

The Ministry reaffirmed that it has prepared all necessary factual, legal, and academic materials for the upcoming proceedings.

Regarding the simmering tensions along the Thai-Cambodian land border, the Ministry stated that the maritime dispute resolution process will be kept separated from the land dispute, reaffirming that any incidents along the land border will not lead to termination of the maritime negotiations.

Thailand and Cambodia entered into the Memorandum of Understanding regarding the Area of Overlapping Claims between Thailand and Cambodia in 2001. The MoU provided the framework for negotiating their maritime disputes in an area which covers around 26,000 sq km. 

During the 2026 election campaign, Anutin Charnvirakul’s Bhumjaithai Party pledged that if elected, the party would cancel the 2001 MoU. 

The Bhumjaithai Party eventually won the election. The Thai cabinet then approved the cancellation of the 2001 MoU, given that no progress had been made in maritime negotiations. Thailand later announced that mechanisms under UNCLOS would be used to resolve the maritime dispute with Cambodia.

Cambodia later responded that it would also adopt UNCLOS mechanisms as its primary approach for resolving the maritime dispute. At that point, the two countries appeared to be on the same page.

The compulsory conciliation proceedings under UNCLOS in this case were initiated by Cambodia. 

Since UNCLOS came into force in 1994, compulsory conciliation has been used only once, in the Australia–Timor Leste case, making this only the second case in the history of the international law of the sea.

Under UNCLOS, compulsory conciliation does not require the consent of all parties involved. Any party wishing to invoke it may submit a written notification to the other party. Failure of the other party to respond is no bar to the proceedings.

According to Article 298, a state is allowed to opt out of a certain dispute resolution mechanism under UNCLOS, but is bound to accept Section 2 in Annex V, which deals with compulsory conciliation.

Thailand has declared that it does not accept arbitration through the courts regarding maritime boundary delimitation disputes. Even though Cambodia cannot take the case to the international courts, as occurred in the dispute over the Preah Vihear Temple, compulsory conciliation is an alternative approach that Cambodia can use.