By Evan Liu
Scarborough Shoal photographed from the International Space Station, October 24, 2015. File photo, not the September 2026 drills. NASA / Johnson Space Center, Wikimedia Commons, public domain. Unmodified.
China announced joint naval and air training around Scarborough Shoal while its coast guard described boarding, interception and towing drills nearby. The more important story is not another South China Sea exercise, but how Beijing uses different layers of maritime power to maintain pressure without crossing directly into military conflict.
On September 27, China’s People’s Liberation Army Southern Theater Command said it conducted joint naval and air training around Scarborough Shoal. On the same day, the China Coast Guard reported exercises involving vessel inspections, interception and forced towing in nearby waters. These descriptions come from the Chinese authorities.
Scarborough Shoal — known as Huangyan Dao in China and Bajo de Masinloc in the Philippines — lies about 120 nautical miles west of the Philippine island of Luzon. China has maintained effective control since a 2012 standoff, while the Philippines also claims the shoal and rights in the area.
A 2016 arbitral tribunal ruled that Scarborough Shoal itself cannot generate an exclusive economic zone or continental shelf. The ruling did not decide sovereignty over the shoal. China rejects it.
The latest activity raises an important question: why does Beijing need both the coast guard and the military in the same contested waters?
Coast Guard in Front, Military Power Behind
The most important distinction between a coast guard vessel and a warship is not necessarily firepower. It is legal and political status.
A naval vessel clearly represents military power. A coast guard can frame boarding, interception and expulsion as law enforcement, allowing a state to exert pressure without immediately crossing the threshold into military conflict. That framing does not itself establish that an action is lawful in disputed waters.
The September 27 announcements illustrate that division. The coast guard described practicing control of vessels, while the PLA reported naval and air training. They do not need to perform identical missions to create a layered system of pressure.
Scarborough Shoal Is Becoming a Permanent Front Line
The more important development is not a single exercise, but the growing frequency of Chinese coast guard activity around the shoal.
According to the Asia Maritime Transparency Initiative (AMTI) at CSIS, Chinese coast guard vessels accumulated 1,099 ship-days around Scarborough Shoal in 2025. In the first half of 2026 alone, that figure had already reached 933 — about 85% of the previous full-year total.
A ship-day counts one vessel present for one day: several vessels on the same day add several ship-days. It is a measure of cumulative presence, not a count of calendar days. AMTI’s estimate uses vessel-tracking data and should not be read as a complete record of every ship at sea.
That suggests Beijing is moving beyond occasional demonstrations of presence toward a dense and persistent maritime presence. The question changes from how many Chinese ships arrived today to who can routinely manage access to the waters. Such practical control does not settle legal sovereignty.
This is at the heart of gray-zone competition — pressure below the threshold of open armed conflict — in the South China Sea. Water cannons are not missiles, and coast guard cutters are not destroyers. But persistent patrols, interceptions and enforcement actions can still change realities at sea without a formal conflict.
The Most Dangerous Part Is the Blurring Line
China’s maritime presence around Scarborough Shoal can be understood as several overlapping layers: coast guard presence, maritime militia activity and military power in the background. Maritime militia refers to civilian-looking vessels and personnel used to support state maritime objectives; it does not mean every fishing vessel is part of such a force.
This structure allows Beijing to apply pressure below the threshold of open military conflict. But it also creates greater room for miscalculation. When coast guard vessels, warships and military aircraft operate around the same contested waters, an encounter initially described as law enforcement can escalate quickly.
That is why the September 27 activity matters. Scarborough Shoal shows how persistent presence and gradually escalating pressure can change realities at sea without a shot being fired.
The most dangerous moment in the South China Sea may therefore not begin with a major naval battle. It may begin when an encounter officially described as law enforcement unexpectedly crosses an increasingly blurred military line.
About This Article
This analysis draws on Chinese official announcements reported by Reuters, the 2016 South China Sea arbitration award and AMTI data. China and the Philippines dispute sovereignty and maritime rights surrounding Scarborough Shoal. Information reflects material available as of September 28, 2026.
By Evan Liu. Republished from Asia Horizon Review on Medium, with editorial clarification and replacement photography for the AHR edition.
Sources checked by AHR: Reuters, September 27; AMTI: Occupational Risk; PCA: South China Sea Arbitration.