Manila – The discovery of underwater drones in Philippine waters, with forensic evidence pointing to potential Chinese origins, has ignited fresh concerns over national security and territorial sovereignty in the West Philippine Sea. Philippine authorities revealed on April 16, 2025, that three of five recovered submersible drones likely originated from China, with data suggesting they were used to map the country’s seabed—an act with significant military implications.
Uncovering the Drones: A Pattern of Discovery
Over the past few years, the Philippine Navy has recovered five underwater drones across various coastal regions. The first was found in Pasuquin, Ilocos Norte, in July 2022, followed by others in Zambales in September 2022, Calayan Island in August 2024, Initao, Misamis Oriental, in October 2024, and most recently, San Pascual, Masbate, on January 1, 2025. These discoveries, often made by local fishermen, have raised questions about foreign activities in Philippine maritime territory.
Commodore Roy Vincent Trinidad, the Navy spokesperson for the West Philippine Sea, disclosed during a press briefing at Camp Aguinaldo in Quezon City that forensic investigations conducted on three of the drones indicate a high probability—between 55 and 80 percent—that they were deployed by entities linked to the Chinese Communist Party. “There is a 55 to 80 percent likelihood that these were deployed by the Chinese Communist Party” said Trinidad, attributing the estimate to specific components found within the devices. 
Further evidence came from a SIM card analysis of one drone, which revealed its last contact was with a location in mainland China. “Based on the technical study or forensics of the SIM card, the last contact that it had was in mainland China” said Trinidad. While this does not conclusively prove state involvement, it adds to mounting suspicions about the purpose and origin of these unmanned devices.
Capabilities and Implications: Mapping the Seabed
The drones, according to naval officials, are equipped with advanced technology capable of collecting and transmitting data via satellite communications. This includes bathymetric data—measurements of water depth—along with information on salinity, temperature, and sound propagation. Such data holds value across multiple domains, from academic research to commercial exploration, but its potential military applications are particularly alarming for a maritime nation like the Philippines.
“The data received focuses more on bathymetric data, depth of water, salinity, temperature, propagation of sound. All of these have applications across different fields, academic research, commercial purposes, and also military use” said Trinidad. He emphasized that mapping underwater terrain is critical for any potential adversary, especially in an archipelagic country where underwater warfare could play a decisive role in conflict.
Jonathan Malaya, assistant director general and spokesperson of the National Security Council, reinforced these concerns. “The forensic examination on the submersible drones have allowed us to conclusively determine that they are of Chinese origin” said Malaya. He added that they were likely deployed to map the Philippines’ underwater terrain, describing the findings as “alarming because of [their] implications [on] national security.”
Undersecretary Alexander Lopez, spokesperson for the National Maritime Council, noted that the drones bore Chinese markings and could serve both military and non-military purposes. “Why are they here or why were they used here? Again, for military and nonmilitary purposes. Again, that is for intelligence gathering whether it is military or nonmilitary” said Lopez. The dual-use nature of the technology complicates the narrative, as it raises questions about intent and accountability.
Geopolitical Context: Tensions in the West Philippine Sea
The West Philippine Sea, a portion of the South China Sea within the Philippines’ exclusive economic zone, has long been a flashpoint for territorial disputes. China claims vast swathes of the area under its controversial “nine-dash line,” a demarcation rejected by an international arbitral tribunal in 2016. The presence of these drones, if confirmed to be of Chinese origin, could be seen as a further encroachment on Philippine sovereignty, adding to existing tensions over fishing rights, resource exploration, and military presence in the region.
While Philippine authorities have stopped short of directly accusing the Chinese government, the implications of the findings are hard to ignore. The likelihood of state involvement, as suggested by the forensic data, aligns with broader concerns about China’s maritime activities in the South China Sea. Over the past decade, Beijing has built artificial islands, deployed naval vessels, and engaged in confrontations with Filipino fishermen and coast guard personnel in disputed waters.
For the Philippines, an archipelago of over 7,000 islands, underwater intelligence is as critical as terrestrial or aerial data. Knowledge of seabed topography could provide strategic advantages in submarine warfare, naval navigation, or even the placement of underwater infrastructure. If the drones are indeed gathering data for military purposes, as suggested by officials, this could represent a significant breach of national security.
Response and Vigilance: A Call to Action
In light of these findings, Philippine officials have called for heightened vigilance and increased maritime patrols. Malaya urged the public to report suspicious activities to law enforcement and intelligence agencies, expressing gratitude to the fishermen who turned over the recovered drones. “We thank the fishermen who recovered these drones and turned them over to the authorities” he said.
The government’s response also includes international collaboration. The forensic analysis of the drones was conducted with assistance from the United States, a key ally under the Mutual Defense Treaty. This partnership underscores the broader geopolitical stakes, as Washington has repeatedly affirmed its commitment to supporting Manila in defending its maritime rights against external threats.
Yet, questions remain about the adequacy of current measures to monitor and protect Philippine waters. The drones’ ability to operate undetected for extended periods highlights gaps in maritime surveillance, particularly in remote coastal areas. Expanding patrols and investing in advanced detection technology could be necessary steps, though such initiatives would require significant resources and coordination.
Broader Implications: Regional and Global Concerns
The discovery of these drones is not an isolated incident but part of a larger pattern of underwater espionage and surveillance in contested maritime regions. Other Southeast Asian nations, including Vietnam and Indonesia, have reported similar findings in their waters, raising concerns about a coordinated effort to map the region’s seabed. If confirmed, such activities could have far-reaching implications for regional stability, particularly in areas already fraught with territorial disputes.
Moreover, the dual-use nature of the technology complicates diplomatic responses. While the drones’ data could theoretically be used for benign purposes—such as scientific research or commercial exploration—the context of their discovery and their potential military applications make it difficult to dismiss security concerns. For now, Philippine authorities have adopted a cautious tone, emphasizing the need for further investigation while avoiding direct accusations that could escalate tensions.
Looking Ahead: Balancing Security and Diplomacy
As the Philippines grapples with the implications of these underwater drones, the challenge lies in balancing national security with diplomatic relations. While the evidence points to a likely Chinese origin, no definitive link to state actors has been established. Any response must therefore be measured, grounded in verified facts, and aligned with international law to avoid unnecessary provocation.
At the same time, the discoveries underscore the urgency of strengthening maritime defenses and fostering regional cooperation. The South China Sea remains a critical theater for geopolitical competition, and incidents like these serve as reminders of the complex interplay between technology, security, and sovereignty. For Filipino communities along the coast, the presence of foreign drones in their waters is not just a matter of policy but a tangible threat to their way of life.
As investigations continue, the Philippine government faces mounting pressure to protect its maritime borders while navigating an increasingly fraught regional landscape. Whether these drones represent a deliberate act of espionage or a misunderstanding remains to be seen, but their discovery has undoubtedly cast a shadow over the already turbulent waters of the West Philippine Sea.
