Scarborough Shoal: A Flashpoint in US-China Rivalry

Tensions around Scarborough Shoal are once again placing the Philippines, China, and the United States in increasingly close military contact. This situation transforms a small cluster of reefs and rocks west of Luzon into one of the most closely watched flashpoints in the South China Sea. Under US President Donald Trump, American forces have continued operating with the Philippines and other regional partners as Manila seeks to protect its maritime interests, while Beijing maintains a heavy presence. The situation has grown more complicated as military exercises, Coast Guard confrontations, and alliance commitments increasingly overlap in the same operating environment.

One of the clearest demonstrations of increased cooperation came during a multilateral maritime cooperative activity conducted from July 21st to July 25th-26th in waters west of the Philippine province of Zambales. Philippine, Japanese, and American forces took part in the operation inside the Philippine exclusive economic zone. The official US Navy account listed the Independence-class littoral combat ship USS Santa Barbara and a P-8A Poseidon American patrol aircraft among the American participants, while Japan deployed the destroyer JS Kirisame.

Philippine military officials later disclosed that the American presence during the exercise was even larger than initially reported. Rear Admiral Roy Vincent Trinidad, the Armed Forces of the Philippines (AFP) spokesperson for the West Philippine Sea, stated that the US had a carrier strike group, a large formation of warships, participating. According to the AFP, this formation was headed by the nuclear-powered aircraft carrier USS George Washington. The carrier was operating in the Philippine Sea during the opening of the five-day activity, and its participation carried significant strategic importance.

A carrier strike group's presence close to the West Philippine Sea sent an unmistakable strategic message, as these groups are designed to project air and naval power across vast distances. Washington demonstrated its ability to move major naval forces into waters near the Philippines while operating alongside regional allies. Scarborough Shoal, known in the Philippines as Bajo de Masinloc, and its surrounding maritime area falls within 200 nautical miles of the Philippines, but sovereignty over the Shoal itself remains contested between Manila and Beijing. An important legal distinction is that the 2016 South China Sea arbitration did not determine ownership.

The 2016 South China Sea arbitration did not determine which country owns Scarborough Shoal because the tribunal lacked jurisdiction to decide territorial sovereignty. However, it did determine that Scarborough Shoal cannot generate its own exclusive economic zone and found that the feature has historically been used as a traditional fishing ground by fishermen from the Philippines, China, and other countries. China has maintained an almost continuous Coast Guard presence around the shoal since the 2012 standoff with the Philippines, giving Beijing substantial practical control over access to the area. Manila's National Task Force for the West Philippine Sea asserts that Bajo de Masinloc is and will always be an integral part of Philippine territory.

The Philippines' position on Scarborough Shoal remains fundamentally opposed to China's. Beijing claims sovereignty over Huangyan Dao (its name for Scarborough Shoal) and accuses Philippine government vessels of illegally entering waters under Chinese jurisdiction. China has also repeatedly criticized growing American, Japanese, and Australian military involvement around the Philippines. These rival positions are producing increasingly dangerous encounters at sea. On July 23rd and July 24th, Chinese Coast Guard ships used water cannons and carried out aggressive maneuvers against Philippine vessels. The confrontations occurred as Philippine Coast Guard and Bureau of Fisheries and Aquatic Resources vessels were delivering fuel and other assistance.

During the July 24th incident, the Philippine Coast Guard reported that Chinese vessel 3107 fired a water cannon at BRP Cape San Agustin while the Philippine ship was about 15 nautical miles from Bajo de Masinloc. Later that morning, China Coast Guard vessel 21581 used a water cannon against fisheries vessel BRP Datu Paduhin, approximately 12 nautical miles northeast of the Shoal. Philippine authorities said personnel received minor injuries. China presented an entirely different account, with its Coast Guard stating that Philippine vessels had ignored warnings and entered waters Beijing considers its territorial waters.

Chinese authorities acknowledged implementing measures including verbal warnings, blocking control operations, and water cannon spraying, describing these actions as lawful enforcement. The timing was especially sensitive because American, Philippine, and Japanese forces were conducting their multilateral activity in the broader region. Instead of reducing its presence as Chinese pressure increased, Manila was simultaneously conducting civilian maritime missions and operating militarily with two major security partners. This growing network of exercises is intended partly to improve interoperability and demonstrates that Manila is no longer approaching the West Philippine Sea as an isolated bilateral confrontation.

Beijing responded with another demonstration of force. On August 1st, the People's Liberation Army Southern Theater Command conducted joint naval and air training around Scarborough Shoal. Chinese authorities stated that the exercises were designed to improve combat capabilities and protect what Beijing describes as China's territorial sovereignty and maritime rights. China portrayed the activity as a response to actions by regional countries that it accused of damaging peace and stability. These competing exercises illustrate the larger strategic problem developing in the region, as Philippine and allied forces increase cooperation while China shows no intention of reducing its own naval, air, or coast guard operations.

This pattern has continued throughout 2026. US and Philippine forces have repeatedly conducted maritime activities near contested waters, while Chinese vessels have monitored and shadowed some of those formations. The result is an operating environment where such proximity carries serious risks. An aggressive maneuver, mechanical problem, navigational mistake, or misunderstanding between commanders could rapidly turn a controlled confrontation into an uncontrolled incident. The stakes are higher because the Philippines is a formal treaty ally of the United States, bringing the 1951 US-Philippines Mutual Defense Treaty into play.

The Philippines is a formal treaty ally of the United States, and the 1951 US-Philippines Mutual Defense Treaty remains central to Washington's security commitment. During President Ferdinand Marcos Jr.'s July 21st, 2025, visit to the Pentagon, Defense Secretary Pete Hegseth publicly reaffirmed the alliance. Hegseth stated, "Together, we remain committed to the mutual defense treaty." He also made it clear that the pact applies to armed attacks on the two countries' armed forces, aircraft, and public vessels, including their Coast Guard.

Much of China's maritime pressure operates inside a difficult 'gray zone' below conventional armed conflict. The extensive use of the China Coast Guard allows Beijing to exert pressure without necessarily crossing an obvious threshold for military escalation. That ambiguity is one reason joint exercises have become increasingly important to Manila, providing training and visible international support. Washington, in turn, demonstrates its commitment to its allies. Beijing, meanwhile, has to consider how aggressively it can operate when American, Japanese, or Australian forces are nearby. The strategic picture changed again in August when the USS George Washington carrier left the region.

The USS George Washington carrier entered the US Central Command area in August to relieve the heavily deployed USS Abraham Lincoln. This move temporarily left the Western Pacific without a US aircraft carrier and highlighted the pressure created by Washington's military commitments in multiple regions. However, that deployment did not end US military activity around the Philippines. From August 19th through August 25th, Australian, Philippine, and American forces conducted another multilateral maritime activity. The operation included the USS Santa Barbara, Philippine frigate BRP Diego Silang, and the Australian replenishment ship HMAS Supply, along with Philippine Coast Guard and military aircraft.

This exercise demonstrated Washington's ability to maintain regular cooperation using smaller surface combatants and aircraft, even when a carrier was no longer available in the Western Pacific. China, meanwhile, has shown little sign of significantly reducing its maritime presence. The latest Philippine military figures underline the scale of that activity. On September 1st, the AFP reported that it had monitored 56 Chinese Coast Guard and naval vessels across four key areas of the West Philippine Sea during August, specifically 41 China Coast Guard ships and 15 People's Liberation Army Navy vessels. Manila is responding by strengthening both its presence at sea and its military capabilities.

Philippine Defense Secretary Gilberto Teodoro Jr. stated in August that the country intends to expand its unmanned capabilities through the development and acquisition of drones. The government is also seeking additional guided missile corvettes and other major assets as the Armed Forces of the Philippines shifts greater attention toward external defense under President Marcos. At the same time, Manila has expanded security cooperation with the United States, Japan, Australia, and other partners. China views much of this activity through the lens of its wider strategic competition.

Beijing argues that outside powers are complicating territorial disputes and threatening regional stability. Washington, conversely, states that its presence supports freedom of navigation, international law, and the security of its allies. Neither side appears ready to retreat. For President Trump, the challenge is to maintain the credibility of American commitments in Asia while US forces are simultaneously facing demanding operations elsewhere. For President Marcos, every Philippine mission near Bajo de Masinloc tests whether Manila can continue exercising its claimed rights and maintaining a presence despite pressure from a far larger power.

As of September 2026, the situation remains unchanged. Scarborough Shoal forms part of a much broader contest over China's strategic position in the South China Sea. This is why a relatively small maritime feature has become strategically enormous. American warships, Philippine frigates, Chinese Coast Guard cutters, military aircraft, and civilian government ships are increasingly operating in the same contested environment. Routine missions now carry increased risk; every patrol sends a message, every interception is watched, and every aggressive maneuver creates another opportunity for escalation. For now, the struggle around Scarborough Shoal remains below the threshold of open warfare, but the margin for error is narrowing.

The margin for error is narrowing as the Philippines continues its patrols and expands cooperation with its allies. China continues Coast Guard deployments, naval operations, and military exercises. The United States continues demonstrating that its defense relationship with Manila remains active, even as American forces respond to demands in other regions. None of the three governments has shown any intention of abandoning its core position. This leaves Bajo de Masinloc not simply as a dispute over fishing grounds or maritime boundaries, but as one of the key indicators of a broader power struggle in the South China Sea.