IOJI Maritime Domain Awareness Report, May-September 2025
Jakarta, November 20, 2025 – Maritime security threat in the form of illegal fishing continue to occur frequently within Indonesia’s waters and jurisdiction, particularly in two areas; the boundary of the Indonesia – Vietnam Exclusive Economic Zone (EEZ) in the North Natuna Sea, and the Indonesia – Philippines EEZ boundary in eastern and central Indonesian waters. These findings are part of the Maritime Domain Awareness Report for the Period of May – September 2025, released by Indonesia Ocean Justice Initiative (IOJI). The report also reveals suspected violations by Chinese oceanographic research vessels and China Coast Guard patrols in the North Natuna Sea, as well as activities cause of damage to the Timika-Merauka submarine cable segment.
The report was launched during a public discussion held on November 14th, 2025 in Jakarta, attended by Director of Fleet Operations Control, Directorate General of Marine and Fisheries Resources Surveillance, Saiful Umam, and Deputy for Policy and Strategy at the Indonesian Maritime Security Agency (BAKAMLA RI), Didong Rio Duta Purwokuntjoro.
“Safeguarding Indonesia’s maritime security, which covers an area of 6.4 million square kilometers, is a shared responsibility. Through this report, IOJI hopes to support the government’s efforts, and to continue encouraging improvements in Indonesia’s maritime regulations and policies,” said IOJI Program Director, Andreas Aditya Salim.
Saiful Umam stated that, “The Indonesia Government continues to conduct surveillance and law enforcement to eradicate illegal fishing through various methods, including the implementation of integrated surveillance system, follow-ups on public reports, and stronger collaboration with relevant parties such as IOJI.”
Didong Rio Duta Purwokuntjoro stated that, “Submarine cables are vital infrastructure, the backbone of global and national communications linked to the internet, banking and government networks. Indonesia urgently needs to establish strong legal and institutional protection for submarine cables.”
The report is part of IOJI’s regular publication series, and it was developed using data analysis tools such as Marine Traffic, Global Fishing Watch, and Skylight, supported by multiple vessel monitoring data sources (Automatic Identification System, satellite imagery, Visible Infrared Imaging Radiometer Suite, Vessel Monitoring System), and artificial intelligence technologies.
Suspected Illegal Fishing by Vietnamese and Philippine Vessels
The IOJI report shows that illegal, unreported and unregulated (IUU) fishing by foreign vessels remains widespread in the North Natuna Sea, particularly by vessels strongly suspected to originate from Vietnam. According to IOJI Senior Analyst, Imam Prakoso, “Between May and August 2025, we detected the distribution of Vietnamese fishing vessels across the North Natuna Sea. Based on our analysis, almost all were suspected of using pair trawl gear, which is highly destructive to seabed ecosystems.”
Each year, Vietnamese vessel intrusions occurred in two waves; from March to May, and September to November. These vessels are often accompanied by fish carrier vessels or Vietnamese government vessels. “Satellite imagery between May and August 2025 revealedat least 110 Vietnamese fishing vessels operating illegally in Indonesia’s EEZ in the North Natuna Sea,” Imam Prakoso added.
Further monitoring within Fishery Management Areas (WPP) 716 and 717 identified the presence of “dark objects” or entities not transmitting AIS signals but still detectable via satellite imagery and light detection technologies. These findings suggest numerous fish aggregating devices (FADs) and vessels near Indonesia’sEEZ boundaries with the Philippines and the high seas in eastern and central Indonesia, pointing to potential illegal activities, including illegal fishing and illegal transshipment.
According to IOJI Program Officer, Laura Nindya, under the United Nations Convention on the Law of the Sea (UNCLOS), coastal states have sovereign rights to explore, exploit, manage, and conserve resources within their EEZs. Other states exercising rights (such as navigation) within these zones must show due regard for the coastal state’s rights and duties as well as comply with its laws and regulations as per UNCLOS and international law. Indonesia’s Fisheries Law further stipulates that any person or entity engaging in fishing within Indonesia’s fisheries management areas must possess a Business License, and the placement of FADs likewise requires official permits.
Suspected Activities of Chinese Research Vesses and China Coast Guard Patrols
IOJI also detected ongoing operations by China Coast Guard vessels and a Chinese oceanographic research vessel, Nan Feng, at three different points in the North Natuna Sea between May and September 2025. The China Coast Guard vessel CCG 5204 was again detected entering Indonesian waters in September 2025, likely related to China’s unilateral nine-dash line claim, which was ruled contrary to international law by the Permanent Court of Arbitration in 2016.
According to IOJI Program Officer, Alif Lathif, marine scientific research is a sovereign right under Article 56 of UNCLOS. Any research within Indonesia’s maritime zones requires prior approval from the Government of Indonesia. Indonesia, in accordance with UNCLOS, can take necessary action against parties breaching this sovereign right. Indonesia regulates marine scientific research under Law No. 32/2014 on Marine Affairs and Law No. 11/2019 on the National Science and Technology System. Article 55 of the Marine Law stipulates that marine research within Indonesia’s fishery management areas must obtain government permits, involve Indonesia researchers, and report the results to the government.
Detected Causes of Damage to the Timika-Merauke Submarine Cable
Indonesia’s digital connectivity relies heavily on submarine communication cable systems (SKKL). In the Arafura Sea, several incidents of submarine cable damage have been detected, strongly suspected to be caused by intense fishing activities in the area. “IOJI detected recurring damage along the SKKL Timika-Merauke segment (SMPCS Packet 2) as linked to the movements of cable-laying vessels and fishing boats intersecting submarine cable routes,” said Imam Prakoso.
According to Didong Rio Duta Purwokuntjoro, “Submarine cables are one of the eight key maritime security issues. In Indonesia, management of submarine cable remains sectoral, and there is still no comprehensive national legal framework. Current laws, Law No. 32/2014 on Marine Affairs and Law No. 36/1999 on Telecommunications, do not yet explicitly address spatial planning or cable safety zones.”
Alif Lathif added that submarine cables are governed by UNCLOS, the 1884 Submarine Cable Convention, and national laws such as the Telecommunications Law. Further improvements are needed to designate submarine cables as national vital objects, and at an operational level, to intensify awareness among vessel captains operating in Indonesia’s waters regarding submarine cable routes.
The full report, including IOJI’s legal analysis and recommendations, can be accessed here: https://bit.ly/LaporanMDA-25-IOJI.
Media Contact:
Waraney Rawung, waraneyhr@oceanjusticeinitiative.org
