In Brief
Despite persistent objection to China’s nine-dash line claim under the former Widodo administration, President Prabowo Subianto now risks giving in to Chinese maritime interests. While potentially motivated by economic interests, the joint development proposal risks sacrificing Indonesia’s sovereign rights. Senior officials must convince Prabowo to abandon any further negotiations.
At the Antalya Diplomacy Forum in April 2025, Indonesian President Prabowo Subianto outlined his vision for enhancing global security and prosperity. He raised the controversial Indonesia–China joint development proposal in overlapping maritime areas. The considerations underlying his proposal risk sacrificing territorial integrity in the hope of Chinese investment that can support jobs and economic growth.
In November 2024, for the very first time, Indonesia recognised an overlapping maritime claim with China and proposed a joint development agreement. This sparked pushback from the Indonesian public and members of parliament, who feared it legitimised China’s illegal nine-dash line claim. Despite the Indonesian Ministry of Foreign Affairs clarifying that Indonesia does not recognise any claims that lack a basis in international law, the Chinese government promptly expressed its readiness to negotiate further.
Prabowo’s remarks at the Antalya Diplomacy Forum confirm that the joint development was his idea. He stated, ‘I also proposed joint development with the People’s Republic of China, President Xi. We respect each other’s legal position, but in the meantime, why don’t we work together? We have an overlapping maritime area’. His approach raises legal and security issues for Indonesia.
Prabowo bases his joint development proposal on historical claims rather than international law. He stated that the ‘PRC claims historically for thousands of years Chinese fisherman have fished in those waters, and we claim for thousands of years Indonesian fisherman have fish in those waters. So, I said to President Xi, why don’t we have joint development?’
This ignores the fact that, because Indonesia is a party to the United Nations Conventions on the Law of the Sea (UNCLOS), it does not need to follow China’s historical claims approach. Rather, Indonesia should insist on cooperation with China that is solely based on UNCLOS principles.
Indonesia’s rights stem from UNCLOS provisions for its 200 nautical mile exclusive economic zone. Meanwhile, China’s claim rests on vague historical assumptions under the nine-dash line. A joint development agreement that is not grounded in international law principles is neither appropriate for legal certainty nor protecting Indonesia’s rights.
The scope of the joint development proposal entails also remains unclear. Prabowo’s remarks suggest that the proposal will focus mostly on fisheries, with both countries issuing licences to their fishers in supposedly overlapping maritime areas. But, under international law, Indonesia and China do not have any overlapping maritime areas.
Due to its sovereign rights under UNCLOS article 56, there is no reason for Indonesia to grant fishing concessions to foreign vessels based on claims unsupported by international law. Indonesia cannot claim compliance with international law while basing joint development principles outside UNCLOS.
Prabowo expressed surprise at Chinese President Xi Jinping’s quick acceptance of his proposal, seemingly unaware that Indonesia has rejected China’s previous advances for a joint development proposal with Indonesia. It is clear why China has been proposing this joint development — Indonesia’s agreement to joint development within the nine-dash line area would implicitly recognise China’s claim. For this reason, during the ten years of president Joko Widodo’s administration, Indonesia persistently reiterated that it had no overlapping claim with China and would not agree to any joint development proposal.
Without paying attention to the former government’s insistence on legalism, it seems that Indonesia has switched track and risks sleepwalking into China’s nine-dash line trap.
Prabowo’s remarks at the Antalya Diplomacy Forum indicate that he does not see the previous joint statement as a mistake. There is also a possibility that he will proceed with the implementation of the joint development proposal even though it is clearly against international law and Indonesia’s interest.
Questions remain over why Prabowo made these remarks at the Antalya Diplomacy Forum and what motivated his joint development proposal. China’s economic importance to Indonesia offers one explanation. Prabowo has committed to increasing Indonesia’s annual economic growth to 8 per cent, which requires significant foreign investment. China represents the largest potential source of economic development capital, making the joint development proposal a potential tool to secure China’s investment.
Despite this interest in economic cooperation, Indonesia should not sacrifice its internationally recognised sovereign rights over its exclusive economic zone. As such, the role of Indonesian senior officials and legal advisors in the government must be to ensure that Prabowo does not proceed with the proposal. They should convince Prabowo of how severely the joint development project will hamper Indonesia’s long-term interests. But this is not an easy task, as it requires them to have the courage to speak truth to power.
About the author
Dr. Aristyo Rizka Darmawan is a non-resident Senior Research Fellow, Assistant Professor of Law at Universitas Indonesia, PhD Scholar at the Australian National University and Research Fellow with the Yokosuka Council on Asia-Pacific Studies.
