May
Taiwan Coast Guard Detects Illegal Survey Activities by China Research Vessel, May 22, 2026
Taiwan Coast Guard Detects Illegal Survey Activities by China Research Vessel Tong Ji; Taiwan Coast Guard Vessels Conduct Full-Time Monitoring and Firmly Expel Intruding Vessel
Following the detection on May 7 of the China research vessel Tong Ji deploying scientific instruments approximately 29 nautical miles southeast of Eluanbi to conduct unauthorized survey activities in Taiwan’s waters, after which the TCGA cutter Cheng Kung ordered the vessel to depart by radio broadcast.
Taiwan Coast Guard Administration(TCGA) again detected the same vessel on May 15 at 17:15, approximately 33 nautical miles east of Hualien Port (6.3 nautical miles outside the Restricted Water), deploying scientific survey equipment without authorization.
TCGA immediately dispatched the cutter Lan Yu, which conducted close-range response operations, including wake interference and illumination measures to disrupt the vessel’s activities, ultimately compelling the vessel to retrieve its equipment and depart Taiwan’s waters.
Beginning on May 15, the Tong Ji maneuvered along the outer perimeter of Taiwan’s Restricted Water and operated off the eastern coast near Hualien before returning to Xiamen Port, China, on May 20. During this period, the vessel deployed multiple scientific instruments, including CTD profilers (conductivity, temperature, and depth sensors), turbulence measurement devices, and gravity coring equipment, indicating likely activities involving oceanographic sampling and seabed survey operations.
TCGA assesses that such data may contribute to the People’s Liberation Army’s accumulation of hydrographic data in the Taiwan Strait, acoustic signature analysis, and anti-submarine warfare databases, carrying strategic implications associated with civil-military fusion and battlefield preparation.
During lawful expulsion operations, the Tong Ji reportedly used radio communications to issue provocative statements, including the claim that 'There is no Republic of China; there is only the People’s Republic of China,' in an overt challenge to Taiwan’s sovereignty.
"This is the Republic of China Coast Guard cutter Lan Yu. Your vessel is operating within Taiwan’s Exclusive Economic Zone. No scientific research activities may be conducted without authorization. Depart immediately."
TCGA then escalated response measures through wake interference maneuvers, bow-crossing disruption tactics, and coordinated aerial surveillance using Coast Guard unmanned aerial systems, employing a multi-layered surveillance and enforcement posture that ultimately forced the vessel to recover its equipment, cease unauthorized activities, and depart Taiwan’s waters.
TCGA noted that China currently operates more than 120 oceanographic research vessels of various types, which have increasingly expanded activities throughout the Indo-Pacific region. Through comprehensive surveillance and intelligence collection, TCGA currently tracks approximately 41 such vessels operating in waters surrounding Taiwan.
Over the past three years, the operational range of these vessels has expanded from the First Island Chain to the Second Island Chain, including Guam, and even as far as the Third Island Chain, including Hawaii, with activities extending into the Indian Ocean, Atlantic Ocean, waters near Australia, and the Arctic Ocean.
TCGA emphasized that Taiwan’s maritime sovereignty will not be challenged. China’s research vessels have disregarded international legal norms and attempted to conduct unauthorized survey activities in Taiwan’s waters.
TCGA calls on China to cease such destabilizing actions. TCGA will continue to uphold a firm law-enforcement stance, maintain close surveillance, proactively deploy Coast Guard assets, and take immediate action to safeguard national sovereignty and maritime security.
TCGA also calls upon like-minded members of the international community to jointly uphold the rules-based international order and ensure peace, stability, and prosperity throughout the Indo-Pacific region.
Following the detection on May 7 of the China research vessel Tong Ji deploying scientific instruments approximately 29 nautical miles southeast of Eluanbi to conduct unauthorized survey activities in Taiwan’s waters, after which the TCGA cutter Cheng Kung ordered the vessel to depart by radio broadcast.
Taiwan Coast Guard Administration(TCGA) again detected the same vessel on May 15 at 17:15, approximately 33 nautical miles east of Hualien Port (6.3 nautical miles outside the Restricted Water), deploying scientific survey equipment without authorization.
TCGA immediately dispatched the cutter Lan Yu, which conducted close-range response operations, including wake interference and illumination measures to disrupt the vessel’s activities, ultimately compelling the vessel to retrieve its equipment and depart Taiwan’s waters.
Beginning on May 15, the Tong Ji maneuvered along the outer perimeter of Taiwan’s Restricted Water and operated off the eastern coast near Hualien before returning to Xiamen Port, China, on May 20. During this period, the vessel deployed multiple scientific instruments, including CTD profilers (conductivity, temperature, and depth sensors), turbulence measurement devices, and gravity coring equipment, indicating likely activities involving oceanographic sampling and seabed survey operations.
TCGA assesses that such data may contribute to the People’s Liberation Army’s accumulation of hydrographic data in the Taiwan Strait, acoustic signature analysis, and anti-submarine warfare databases, carrying strategic implications associated with civil-military fusion and battlefield preparation.
During lawful expulsion operations, the Tong Ji reportedly used radio communications to issue provocative statements, including the claim that 'There is no Republic of China; there is only the People’s Republic of China,' in an overt challenge to Taiwan’s sovereignty.
"This is the Republic of China Coast Guard cutter Lan Yu. Your vessel is operating within Taiwan’s Exclusive Economic Zone. No scientific research activities may be conducted without authorization. Depart immediately."
TCGA then escalated response measures through wake interference maneuvers, bow-crossing disruption tactics, and coordinated aerial surveillance using Coast Guard unmanned aerial systems, employing a multi-layered surveillance and enforcement posture that ultimately forced the vessel to recover its equipment, cease unauthorized activities, and depart Taiwan’s waters.
TCGA noted that China currently operates more than 120 oceanographic research vessels of various types, which have increasingly expanded activities throughout the Indo-Pacific region. Through comprehensive surveillance and intelligence collection, TCGA currently tracks approximately 41 such vessels operating in waters surrounding Taiwan.
Over the past three years, the operational range of these vessels has expanded from the First Island Chain to the Second Island Chain, including Guam, and even as far as the Third Island Chain, including Hawaii, with activities extending into the Indian Ocean, Atlantic Ocean, waters near Australia, and the Arctic Ocean.
TCGA emphasized that Taiwan’s maritime sovereignty will not be challenged. China’s research vessels have disregarded international legal norms and attempted to conduct unauthorized survey activities in Taiwan’s waters.
TCGA calls on China to cease such destabilizing actions. TCGA will continue to uphold a firm law-enforcement stance, maintain close surveillance, proactively deploy Coast Guard assets, and take immediate action to safeguard national sovereignty and maritime security.
TCGA also calls upon like-minded members of the international community to jointly uphold the rules-based international order and ensure peace, stability, and prosperity throughout the Indo-Pacific region.
- Source: 海巡署
- Date: 2026/06/01
