The Philippine Coast Guard (PCG) on Tuesday said it has taken custody of an alleged underwater drone discovered by local fishermen in the waters near Barangay Barangonan, Linapacan, Palawan. 

PCG spokesperson for the West Philippine Sea (WPS) Commodore Jay Tarriela said the recovery sheds light on continuing illegal marine scientific research activities in Philippine waters, as part of a broader pattern involving foreign-origin autonomous underwater vehicles (AUVs).

“On September 28, 2025, fishermen from Sitio Tapic, Brgy. New Colaylayan, Linapacan, discovered the approximately 12-foot-long device during routine fishing operations,” Tarriela told reporters.

“Later that evening, they turned the AUV over to Coast Guard personnel,” he added. 

The device was safely transported and is now secured at PCG Station Linapacan for thorough verification, technical examination, and investigation, in collaboration with relevant national security agencies.

Preliminary inspection reveals the presence of a Conductivity-Temperature-Depth (CTD) sensor—a sophisticated probe used to measure seawater salinity, temperature, and depth, which are critical for oceanographic studies. 

The sensor bears Chinese labeling ("海水盐度传感器") and a serial number (CTD-20090334), alongside signs of corrosion from extended exposure to saltwater. 

Mounted on a durable metal frame, the device’s design is consistent with those found on autonomous underwater vehicles commonly referred to as underwater drones.

Tarriela said the recent recovery is the latest in a series of similar incidents reported since July 2022. 

Previously recovered devices have been found off Pasuquin, Ilocos Norte (July 2022); the Zambales coast (September 2022); Calayan Island, Cagayan (August 2024); Initao, Misamis Oriental (October 2024); and San Pascual, Masbate (December 2024). 

Investigations of at least three earlier recovered units linked them to Chinese deployment, based on evidence such as China Telecom SIM cards, iridium transceivers connected to Beijing-based defense contractor HWA Create, and battery packs marked by China Electronics Technology Group Corporation.

Forensic analysis of these AUVs has revealed their use in advanced underwater surveillance and seafloor mapping. 

The CTD sensors allow the collection of vital oceanographic data, including salinity, temperature gradients, depth, and acoustic propagation—key information for bathymetric charting and environmental monitoring. 

Some devices also demonstrated capabilities for autonomous data processing, onboard storage, and encrypted satellite communications to mainland China.

“The Philippine Coast Guard remains vigilant in safeguarding our maritime domain and protecting the livelihoods of our fisherfolk,” PCG Commandant Admiral Ronnie Gil Gavan said in a statement. 

“We commend the quick action of the local fishermen for reporting this find. This incident highlights the need for continued community awareness and a whole-of-nation approach to deter unauthorized activities in our waters.”

The device is currently undergoing a detailed forensic examination to ascertain its precise origin, operational history, and any security threats it may pose. 

Authorities urged the public to report any suspicious maritime objects to the nearest Coast Guard station.