Captured Underwater Drone Sent Signal to China, Philippines Reveals Amid Rising Maritime Tensions

In a startling development underscoring the rising maritime tensions in the South China Sea, the Philippine military has revealed that at least one of five underwater drones recovered by local fishermen sent a signal back to mainland China. The discovery, made between 2022 and 2024, has raised serious concerns about foreign surveillance and the potential for underwater warfare in strategically sensitive Philippine waters.

These drones, capable of far more than mere navigation, were found in key maritime chokepoints across the archipelago. According to Rear Admiral Roy Vincent Trinidad, spokesperson for the Philippine Navy on South China Sea affairs, the drones had capabilities that could aid in detecting undersea threats, conducting surveillance, and testing underwater weaponry. "This is not just about exploring the sea. This is about the possibility of undersea conflict,” Trinidad emphasized during a media briefing.

While the Philippine military refrained from officially naming the country responsible for deploying these devices, several drones bore Chinese markings. More tellingly, a forensic analysis of a SIM card found on one of the drones confirmed its last communication was traced to mainland China.

One drone was recently discovered off San Pascual, Masbate, on December 30, 2024, by local fisherfolk and has since been handed over to the Philippine Navy. Photos released by the police regional office show a sleek, torpedo-shaped device — designed to blend into deep waters and avoid detection.

In total, three of the drones were found off northern Luzon, including two near the Balintang Channel — a vital waterway just south of Taiwan. The remaining two were recovered near Masbate Island in the central region and close to Mindanao in the south. All locations are considered critical for both national defense and international maritime navigation.

This revelation comes at a time of increasing military readiness. The Philippines is preparing for its annual joint military exercise with the United States, dubbed Balikatan or "shoulder to shoulder." This year’s drills, set from April 21 to May 9, will involve around 10,000 troops and for the first time include a test of integrated air missile defense systems.

Brigadier General Mike Logico, speaking about the exercises, stated, “We are treating exercises as rehearsals. This is a continuation of long-planned joint operations with our allies.” Defense Secretary Romeo Brawner also highlighted that northern Luzon would host the bulk of the drills due to its strategic significance, hinting at potential threat scenarios in the area.

“These are the areas where we perceive the possibility of an attack,” Brawner said, adding that the country must prepare without creating unnecessary panic.

The discovery of these drones is the latest chapter in a tense standoff between Manila and Beijing over contested waters and sovereignty claims in the South China Sea. It also adds a technological layer to the conflict — one that now stretches below the waves, as nations use advanced unmanned systems to expand their reach and gather critical intelligence.

As regional dynamics shift, the presence of foreign underwater drones in Philippine waters underscores the growing risks of covert surveillance and the need for greater maritime vigilance.