Intel Brief: China-Philippines Tensions in the South China Sea Simmer
- gregorio46
- Sep 18
- 5 min read
Date: 18/09/2025 (12:00 UTC+2)
Where?
South China Sea: Scarborough Shoal
Who’s involved?
China, Philippines
What happened?
On 07/08/2025, three Chinese Coast Guard (CCG) Zhaoyu-class cutters, Hailing (3301), Dahao (3304) and Zhongjian (4304), were spotted in the Luzon Strait, approaching the Batanes island group. Batanes is the northernmost Philippine province, located just south of Taiwan. The vessels reportedly did not respond to Philippine radio challenges (requests/demands). This was the first publicly known instance in which the CCG had deployed vessels this far east in Philippine waters.
On 11/08/2025, CCG Jiangdao-class cutter (3104) collided with the Chinese People’s Liberation Army Navy (PLAN) Type 052D destroyer Guilin (164) while the former was chasing Philippine Coast Guard (PCG) Parola-class patrol vessel BRP Suluan (MRRV-4406), which was reportedly delivering supplies to Philippine fishermen near Scarborough Shoal.
On 12/08/2025, China deployed several CCG vessels, as well as some Chinese Maritime Militia (CMM) vessels. The latter is a mix of actual fishing vessels whose crew can occasionally be used in quasi-military operations and purpose-built CMM vessels. These look like fishing vessels, but are usually larger and always much better equipped. These deployments are often referred to as “swarms” due to the sheer number of vessels that approach a given position or asset (i.e. a Philippine vessel). These deployments usually aim to block Philippine vessels from entering a certain area and force them back.
On 13/08/2025, the US carried out a Freedom of Navigation Operation (FONOP) near Scarborough Shoal with US Navy (USN) Arleigh Burke-class destroyer USS Higgins (DDG-76). Independence-class USS Cincinnati (LCS-20) was also spotted nearby, although it was not officially named as being part of the FONOP.
On 13/08/2025, the PLA’s Southern Theater Command spokesperson, Senior Capt. He Tiecheng, stated it had “sent its naval troops to track, monitor, warn and expel the US Navy vessel”. The PCG reported two PLAN Type 054A frigates shadowing and issuing radio challenges to Higgins. The USN refuted the claim that it had been “expelled”, or otherwise halted Higgins’ FONOP due to PLAN actions.
On 10/09/2025, China announced its plans to create a national nature reserve in Scarborough Shoal. The reserve will occupy around 3.523 hectares (35 km²).
On 11/09/2025, the Philippines protested the plan, arguing it serves as a “pretext to eventual occupation”.
On 16/09/2025, the PCG released footage showing two CCG vessels, a likely Zhongtao-class patrol craft (21562) and a Zhaojun-class cutter (5201), harassing Bureau of Fisheries and Aquatic Resources (BFAR) ship BRP Datu Gumbay (MMOV-3014) (Appendix A; A1, A2, A3). The latter was conducting a resupply mission to provide Philippine fishermen in the area with ice and fuel. The CCG used water cannons to harass Datu Gumbay, which resulted in an injured crew member and significant damage to the ship.
On 18/09/2025, the Philippine Department of Foreign Affairs filed a formal diplomatic protest against China’s actions in the 16/09/2025 incident.
Analysis
The contention of Scarborough Shoal dates back to 2012, when China first restricted access to the Shoal, which is within the Philippines’ Exclusive Economic Zone (EEZ). The Philippines expected the US to intervene, as the two countries share a mutual defence treaty and Manila had made clear it saw the blockade of the island as a violation of its sovereignty. The US, however, did not recognise anyone’s sovereignty over the island, Philippines included, and did not intervene. Subsequent Philippine efforts to solve the issue via the Permanent Court of Arbitration (PCA) were, although the court ruled in Manila’s favour, unsuccessful, as China essentially ignored the ruling.
China has since maintained a presence around the Shoal using CCG and CMM assets. Despite this, the Philippines always sought to contest the Chinese presence. China had, from 2013 to 2016 embarked in constructing the so-called “Wall of Sand”, a large-scale land reclamation in the Spratly Islands archipelago which resulted in China effectively taking control over several reefs within the contested archipelago. Manila’s will to maintain presence and pressure over the Shoal was to avoid a similar occurrence.
On 17/07/2024, the CCG interfered with a Philippine resupply mission to BRP Sierra Madre, a deliberately grounded ship that the Philippines has, since 1999, used as an outpost in Second Thomas Shoal, within the Spratly Islands. Although tensions never really de-escalated since 2012 — and Chinese interference on rotation and reprovision missions (RORE) was commonplace — this incident was particularly heated and resulted in both parties almost using deadly force on each other. Since then, tensions in both Second Thomas Shoal and Scarborough Shoal had calmed, especially compared to recent years.
However, the collision on 11/08/2025 reignited China’s anger, arguably due to the public humiliation it had suffered. The plan to create a national reserve around Scarborough Shoal gives China an excuse to unilaterally formalize its claims on the shoal and does so without the need to construct a structure of any sort, at least not immediately. Moreover, it directly challenges the use of the water around the shoal, a known fish-rich area, for fishing. The Philippines, joined by its allies, has already criticized the plan. Still, if the latter goes through, criticism will have a negligible impact on China’s willingness to defend its newly created reserve against “...all types of illegal and irregular activities”, supposedly by any means it deems necessary.
Conclusion
The national nature reserve plan may be only a threat, but the situation remains fragile. A national nature reserve will give China the opportunity to justify harsher harassment against Philippine fishing vessels and their supporting fleet; it will also give China an excuse to erect some sort of construction in the shoal, cementing, literally, Beijing’s claim over it.
If the plan were to materialize, it would also become another way in which Beijing can test Manila’s resolve. It is unlikely that either country wants to deliberately use lethal force, but, if that were the case, Manila’s resolve, and by extension Washington’s, would be thoroughly tested. Philippine President Marcos has already indicated that if Chinese harassment against Philippine vessels were to result in a fatality, the Philippine government would regard it as an act of war. In this regard, the death of a Philippine national at the hands of China is a plausible occurrence, exemplified by the use of high-pressure water cannons against Philippine vessels, which already cause significant damage to the watercraft they target (Appendix A; A4). In an already heated environment in the South China Sea, such an event could result in unpredictable developments.
Appendix A
A1
A2
A3
A4
A5
