Escalating Shadows: Chinese Buildup in the West Philippine Sea Amid Joint Drills

Manila, Philippines – As the calendar flipped from August 15 to 27, 2025, the West Philippine Sea (WPS) – Manila’s designation for its portion of the South China Sea – witnessed a subtle yet unmistakable escalation in tensions. While no direct confrontations like rammings or water cannon assaults marked this period, China’s intensified military presence around key features, coupled with the Philippines’ joint exercises with Australia, underscored the fragile balance in this disputed maritime domain. These developments come against a backdrop of longstanding sovereignty claims, with Beijing rejecting the 2016 arbitral ruling that affirmed Philippine rights in the area.

The period began with the launch of large-scale combat drills between Philippine and Australian forces, dubbed Exercise Alon, running from August 15 to 29. Involving over 3,600 personnel, the exercises featured live-fire drills, battle maneuvers, and advanced assets including an Australian guided-missile destroyer, F/A-18 fighter jets, a C-130 aircraft, Javelin anti-tank weapons, and special forces equipment. Held near the contested waters, these operations aimed to enhance deterrence against threats to freedom of navigation and overflight. 80 Philippine Defense Secretary Gilberto Teodoro Jr. emphasized the drills’ role in boosting interoperability and regional stability during a meeting with Australian Defense Minister Richard Marles on August 22, resulting in a joint statement of intent for deeper defense cooperation.

China, which claims nearly the entire South China Sea, voiced alarm over the maneuvers, viewing them as provocative. This sentiment echoed in Beijing’s actions, as reports emerged of heightened Chinese deployments. On August 20, the Armed Forces of the Philippines (AFP) spotted a significant buildup around Ayungin Shoal (Second Thomas Shoal), including five China Coast Guard (CCG) vessels, 11 rigid-hulled inflatable boats (some armed with high-caliber machine guns), nine maritime militia ships, a helicopter, and an unmanned aerial vehicle. 78 CCG cutters conducted maneuvers and water cannon drills, while smaller boats approached as close as 50 meters to the grounded BRP Sierra Madre – a rusting Philippine outpost symbolizing Manila’s sovereignty since 1999. 80 In one instance, boats dropped a net across a shallow entrance used by Philippine resupply vessels, and a CCG ship fired its water cannon in an apparent drill without targeting.

Philippine Navy spokesperson Rear Admiral Roy Vincent Trinidad described the surge as “concerning,” noting an increase from an average of seven militia and two CCG vessels to around 20 starting August 20. 79 He affirmed that the AFP would maintain surveillance and that contingency plans were in place for escalation. 80 Filipino forces from the Sierra Madre deployed to prevent closer Chinese approaches, highlighting the risk of miscalculation in these close-quarters encounters.

By August 25, the situation evolved with the sighting of a People’s Liberation Army Navy (PLAN) tugboat near the Sierra Madre, accompanied by 13 militia vessels and two CCG ships. 78 This deployment fueled speculation about potential attempts to tow the outpost, but Trinidad dismissed immediate threats, stating, “It will take more than a tugboat to pull out BRP Sierra Madre.” 79 He suggested the tugboat was likely for Chinese use, such as aiding vessels running aground in the shoal’s shallows, rather than an offensive move. 78 By the following day, vessel numbers had dipped slightly but remained elevated, signaling sustained pressure.

These activities reflect broader patterns of coercion. Analysts warn that China’s ramped-up presence – including armed boats and drills – aims to deter Philippine resupply missions and assert dominance in Manila’s exclusive economic zone (EEZ). 78 The Philippines continues routine rotation and reprovisioning for Marines on the Sierra Madre, viewing it as a moral obligation despite past harassments. 78 Teodoro reiterated that altering the stance would undermine national interests, grounding claims in the 2016 ruling Beijing ignores.

Public sentiment bolsters this resolve. An OCTA Research survey released on August 25 (conducted July 12-17) revealed 85% of Filipinos distrust China, with 74% seeing it as the greatest threat – figures reaching 100% in regions like MIMAROPA and Bicol. 78 Teodoro hailed the results as evidence of support for the government’s firm position.

U.S. aerial surveillance monitored the August 20 events, underscoring allied involvement amid fears of broader conflict. 80 As Exercise Alon wrapped up, experts note that such partnerships strengthen Manila’s deterrence but risk provoking Beijing further. With no binding code of conduct in sight, the WPS remains a flashpoint where missteps could ignite wider instability.

As August drew to a close, the Philippine Navy warned of “red lines” – scenarios like attempts to remove the Sierra Madre – that could lead to confrontation. 33 For now, the sea simmers, a testament to unresolved disputes in one of the world’s busiest waterways.

References

Asahi Shimbun. (2025). Australian and Philippine defense chiefs meet as disputes simmer over the South China Sea. Retrieved from https://www.asahi.com/ajw/articles/15980674

GMA Network. (2025). PH Navy: Chinese navy tugboat deployed but not enough to tow away BRP Sierra Madre. Retrieved from https://www.gmanetwork.com/news/topstories/nation/957038/ph-navy-chinese-tugboat-brp-sierra-madre-ayungin-shoal/story/

Maritime Fairtrade. (2025). Philippines says Chinese tugboat seen at Second Thomas Shoal poses no immediate threat. Retrieved from https://maritimefairtrade.org/philippines-says-chinese-tugboat-seen-at-second-thomas-shoal-poses-no-immediate-threat/

UNTV News and Rescue [@UNTVNewsRescue]. (2025, August 26). May mga itinuturing na ‘red lines’ o mga sitwasyon ang Philippine Navy na dapat pag-ingatan ng China upang huwag tuluyang mauwi sa komprontasyon ang tensyon sa West Philippine Sea [Post]. X. https://x.com/UNTVNewsRescue/status/1960320064567263382