Features | Southeast Asia

10 Years After the South China Sea Arbitration: Will ASEAN Remain Silent?

Despite its vocal support for UNCLOS, ASEAN has not recognized a legal judgment brought under the convention’s framework.

The ASEAN Leaders’ Declaration on Maritime Cooperation, adopted at the 48th Summit in Cebu on May 8, 2026, referred to the 1982 United Nations Convention on the Law of the Sea (UNCLOS) no fewer than 18 times, reaffirming the key principles of peace and stability, the peaceful settlement of disputes and compliance with UNCLOS.

Yet ASEAN has never officially recognized the 2016 South China Sea Arbitral Award issued by an arbitral tribunal constituted under Annex VII of UNCLOS – the very convention that ASEAN itself has repeatedly affirmed as the comprehensive legal framework governing all activities at sea. 

July 2026 marks the 10th anniversary of the arbitral ruling in favor of the Philippines in its case against China concerning the South China Sea. How will ASEAN respond to this important legal milestone?

ASEAN’s Historical Response to the 2016 Award

Immediately after the 2016 South China Sea award, ASEAN failed to forge a unified stance. At the 49th ASEAN Foreign Ministers’ Meeting (AMM) held in Vientiane, just two weeks after the judgment, member states could not reach a consensus to include any direct reference to the ruling in the joint communiqué. According to Philippine officials, every proposed reference was vetoed by a member state without explanation or counter-proposal. The same pattern reappeared at the 30th ASEAN Summit in Manila in 2017 and in subsequent years. Nearly a decade on, ASEAN is still struggling to reach any consensus regarding the 2016 award.

Any attempts to predict ASEAN’s response require an examination of how its member states have engaged with the award over the past decade. Given ASEAN’s consensus-based principle, the collective reflects the national interest and policy preferences of individual members.

The sharp divergence among ASEAN member states can broadly be categorized into three groups. The first consists of countries that have openly aligned themselves with China’s position, namely Cambodia and Laos, and to a lesser extent Thailand. Cambodia openly opposed the ruling and vowed to oppose any ASEAN statement endorsing it. As ASEAN chair in 2016, Laos maintained formal neutrality in order to fulfill its responsibilities, yet remained supportive of Beijing’s rejection. Thailand issued a statement on July 12, 2016, that meticulously avoided the words “ruling,” “award,” or “tribunal.” Many observers grouped Thailand alongside Laos and Cambodia, arguing that it displayed a tendency to tilt toward Beijing in pursuit of defense procurement deals and infrastructure investments.

The second group supported or invoked the award to varying degrees, including Vietnam, Indonesia, Malaysia, and later the Philippines. Vietnam adopted the most positive stance within ASEAN, officially “welcoming” the award, and regularly drawn upon the tribunal’s legal findings to defend its own maritime rights and sovereignty claims in the South China Sea.

Indonesia initially responded by calling for restraint and respect for international law. However, in May 2020, Jakarta submitted a Note Verbale to the United Nations Secretary-General that effectively accepted the award’s conclusion showing that the “nine-dash line” has no legal basis. 

Malaysia, maintaining its policy of  “quiet diplomacy,” avoided direct confrontation with Beijing while reportedly relying on elements of the award’s legal reasoning in its 2019 submission to the Commission on the Limits of the Continental Shelf (CLCS) regarding an extended continental shelf claim. 

The Philippines has followed a more shifting course. Under President Rodrigo Duterte, who took office just weeks before the ruling came down, Manila adopted a notably restrained response and actively downplayed the award while pursuing closer economic ties with China. This approach changed markedly under President Ferdinand Marcos Jr., who elevated the 2016 award into a central pillar of the Philippines’ South China Sea strategy.

The third is the neutral or silent group, consisting of Brunei, Singapore, and Timor-Leste. Brunei continued to play the role of  a “silent” claimant in the South China Sea, avoiding direct confrontation and refraining from issuing any official statement on the award. Singapore stated that it had “taken note” of the award and was studying its implications. Nevertheless, during a visit to Washington in 2016, then-Prime Minister Lee Hsien Loong reportedly stressed the importance of respecting the arbitration result, drawing criticism from Beijing. Similarly, Timor-Leste, which was not yet an ASEAN member at that time, also avoided taking a direct stance on the award but insisted UNCLOS as “Constitution of the Oceans.”

ASEAN’s consensus mechanism enabled opponents of the award to block supportive language while the supporters avoid public confrontation. Even if there is active support from Vietnam or the Philippines, it is insufficient to overcome opposition and silence from other members. This structural reality explains why, despite numerous ASEAN Foreign Ministers’........

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