Chinese Drilling Ship Alarms Philippines in EEZ

Operated by the Guangzhou Marine Geological Survey, the 76-meter Haiyang Dizhi Shi Hao spent 25 days within the Philippine Exclusive Economic Zone starting near midnight on August 10, 2026, the Philippine Coast Guard stated.

Operated by the Guangzhou Marine Geological Survey under China's Ministry of Natural Resources, the vessel lingered for approximately three weeks within 12 nautical miles of Bajo de Masinloc, also known as Scarborough Shoal.

In 2023, the vessel reportedly drilled a core sample reaching about 302.07 meters beneath the seafloor, demonstrating its capacity for extensive sub-seabed exploration, which sparked concern given its slow movements in the current unauthorized operation.

Rear Admiral Jay Tristan Tarriela categorized this unauthorized activity as illegal, citing the United Nations Convention on the Law of the Sea (UNCLOS), which requires consent from coastal states for research within their Exclusive Economic Zones.

Following a 2012 standoff, Chinese vessels have maintained control over the shoal, frequently restricting Filipino fishermen, despite the 2016 South China Sea arbitration ruling that affirmed the shoal as a traditional fishing ground but does not generate an EEZ.

Philippine authorities also monitored the vessel near the Philippine Rise in early 2024, tracking its movements using Canada's dark vessel detection system, which identifies ships that deactivate their signals to avoid detection.

The Haiyang Dizhi Shi Hao periodically switched off its Automatic Identification System (AIS) during its latest operation, yet satellite surveillance allowed Philippine authorities to reconstruct much of its movement from August into early September.

Severe weather conditions caused by the southwest monsoon hindered the Philippine Coast Guard’s ability to directly challenge the Chinese ship, leading officials to suggest China may have strategically timed its operations to coincide with these poor weather conditions.

In May 2026, a Chinese floating research platform was deployed near the shoal and later removed in mid-June following diplomatic protests from the Philippines.

Prior to that, on September 10, 2025, China declared the 'Fiery Cross Reef National Nature Reserve' at the shoal, a declaration formally rejected by the Philippines.

Manila fears these 'environmental' projects serve as pretexts for gathering geological data, potentially for future military construction, with the Mischief Reef expansion in the 1990s serving as a cautionary precedent for Philippine security observers.

The Chinese Embassy in Manila, through Deputy Spokesperson Guo Wei, defended the survey as a lawful activity conducted in waters Beijing regards as part of China's territory.

Guo Wei rejected Philippine accusations regarding the vessel's presence, highlighting the ongoing dispute over legal jurisdiction, historical narratives, and scientific authority in the contested waters.

The Philippines continues to employ a strategy of surveillance, diplomatic protest, and adherence to international law to address the situation.

President Marcos Jr. continues to support Coast Guard patrols despite the nation's limited maritime capabilities, with Philippine authorities primarily concerned that the scientific information gathered today could shape future infrastructure developments at Bajo de Masinloc.