Philippine coast guard

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South China Sea Incidents 101 – How China is Ramping up Coercion Against Philippine Vessels

South China Sea Incidents 101 – How China is Ramping up Coercion Against Philippine Vessels

10 kwietnia, 2024

South China Sea Incidents 101 – How China is Ramping up Coercion Against Philippine Vessels

Philippine coast guard

Autor foto: Domena publiczna

South China Sea Incidents 101 – How China is Ramping up Coercion Against Philippine Vessels

Autor: Jakub Witczak

Opublikowano: 10 kwietnia, 2024

Beijing’s claims and maritime incidents in the South China Sea are not a novelty, but recently, the Chinese behaviour and disputes with the Philippines have worsened, with incidents engaging both states’ vessels becoming much more common since 2023. These growing tensions fit into the broader geopolitical context of the Indo-Pacific. 


Dispute Background

The South China Sea (SCS) constitutes one of the Indo-Pacific flashpoints, i.e. zones with a heightened risk of conflict escalation. Various strategic, economic and political factors drive the territorial disputes between local actors, the fiercest and most assertive of which is China. Beijing bases its entitlements on historical rights and invokes the nine-dash line to delineate its claims covering roughly 90% of the SCS. In 1994, the United Nations Convention on the Law of the Sea entered into force, providing states such as the Philippines with legal foundations for establishing exclusive economic zones (EEZs). Naturally, the Philippine EEZ overlaps with Chinese territorial claims.

Despite restrictions under international law, China continues to claim sovereignty over the disputed territories and has used coercive means in attempts to enforce its control. In response to the political stalemate and the 2012 tense situation around one of the disputed areas, Manila filed a case against China to the Permanent Court of Arbitration in 2013.[1] The tribunal decided that Chinese historical rights, its construction of artificial islands in the SCS and its obstruction of Philippine vessels are all illegal. Unsurprisingly, Beijing denounced the ruling and refused to recognise it.[2]


Mounting Incidents

The most severe dispute between the two countries concerns the Second Thomas Shoal, an atoll constituting part of the Spratly Islands and situated within Manila’s EEZ, where, since 1999, a Philippine ship, BRP Sierra Madre, has been stationed. It is a wreck of an ex-US tank-landing ship[3], which Manila placed in the atoll as a countermeasure against Chinese advancement and response to the Chinese occupation of a nearby Mischief Reef a few years earlier.[4] Manila maintains a group of marines at the makeshift military checkpoint and regularly sends its vessels with resupply missions to the Second Thomas Shoal. That is where the Chinese step in with actions aimed at intimidating and impeding Philippine operations. These incidents, however, are not only limited to the area with the marooned Sierra Madre.

Chinese incendiary actions and harassment of Philippine vessels in the disputed zones of the SCS are not new. However, since 2023 a surge in the frequency and intensity of these incidents has been observed, entailing an aggravation of tensions between Manila and Beijing. According to news reports, in 2023, there were several incidents in the disputed zones between Chinese and Philippine vessels. Simultaneously, Chinese territorial claims are also supported by the nearly permanent presence and activity of “swarms” of Chinese ships in the waters of the SCS.[5] Last year, a clash in October was reputedly the first occasion on which Manila reported Philippine ships being rammed by Chinese ones.[6] Moreover, March 2024 brought two additional incidents in the SCS, on the 5th and 23rd March.[7]


A Carefully-Devised Strategy

A few components must be underscored when examining the incidents involving Chinese and Philippine vessels. Firstly, it is worth noticing the techniques Beijing employs to coerce Manila. Measures undertaken against Philippine vessels include encirclements, blockades, collisions, water-cannoning and the sporadic use of “military-grade” lasers, which can temporarily blind the Philippine crews. China applies such means deliberately since they do not entail using military force and, therefore, do not amount to acts of war. Thus, China evades any direct bellicose response from Manila and its American ally, minimising the escalation risk. Additionally, Chinese vessels only target resupply boats, not the Philippine Coast Guard, with their non-lethal assaults, knowing they do not have the capacity to respond.

In addition, China has mastered deploying its coast guard and maritime militias, the so-called “little blue men”, in the disputed waters of the South China Sea. The vessels of these formations conduct operations against the Philippine ships. Even when Beijing dispatches the People’s Liberation Army Navy (PLAN) units, China’s warships usually stay behind. At the same time, the China Coast Guard and maritime militia vessels, which are primarily just “upgraded” fishing boats, execute aggressive manoeuvres and “attack” Philippine ships. The abovementioned moves constitute grey zone tactics, through which China cleverly aims to coerce other states whilst remaining below the threshold of war.[8] Such activities provide China with greater operational flexibility and enhance Chinese political and diplomatic efforts by harassing and hampering Philippine navigation.


Just One Piece of a Larger Puzzle

The qualitative and quantitative intensification of Chinese efforts reflects China’s goal to drive the Philippines away from the Second Thomas Shoal and assert Beijing’s dominance in the area. Nevertheless, tensions between the two states should be considered within the broader regional power game. Since 2022, when Ferdinand Marcos Jr. was sworn in as the Philippines’ new president, Manila has adopted a firmer and stronger anti-China approach compared to the one during the presidency of Rodrigo Duterte (2016-2022). The last two years have seen a reinvigoration of the long-standing military alliance between Washington and Manila, including the advancement of the implementation of the 2014 Enhanced Defence Cooperation Agreement (EDCA).[9] In 2023, US forces were authorised to use an additional four bases on the Philippine territory (an extra four to the five agreed on in 2014), most of which are located in Luzon, just 250 km south of Taiwan.[10] Access to these strategic sites allows the US army to better monitor Chinese activity in the SCS and around Taiwan, while Manila can feel reassured about America’s dedication to its security, including the situation in the SCS.

The 1951 Mutual Defence Treaty with the USA undeniably plays a primordial role for Manila, and it can be argued that, so far, it has successfully contributed to deterring any Chinese armed assault on the Philippines in the South China Sea. China’s use of grey zone tactics and their recent amplification could mean Beijing feels its strategy, accompanied by diplomatic and political pressure, fails to yield the desired results and concessions from the Marcos administration. Intensification of Chinese actions could also signify that Beijing feels more and more emboldened to use these tactics as it has not witnessed much resistance or retaliation for its actions. Hence, China will probably continue provoking maritime incidents and applying coercive actions against Philippine vessels.[11] Washington and Manila should continue signalling a joint commitment to safeguarding the Philippines’ security. It is equally vital that actions such as the deployment of patrols are regularly undertaken to minimise the number of incidents and decrease the risk of escalation. Chinese activity in the South China Sea has also been an important catalyst for strengthening trilateral cooperation between the USA, the Philippines and Japan, all of whom are concerned about Beijing’s rising assertiveness in the region.[12] Japan has also faced Beijing’s grey zone tactics in the vicinity of the disputed Senkaku/Diaoyu Islands.



  • The incidents China causes do not occur accidentally but constitute part of a planned strategy for coercing Manila. China deliberately utilises non-lethal means to avoid any action potentially considered a casus belli. Beijing will probably continue creating incidents with Philippine vessels in the South China Sea as this is currently the aptest option at its disposal. One may also expect a further increase in the frequency of these clashes.
  • Chinese actions against the Philippines in the SCS fall within the larger trend of China’s grey zone tactics intensification in the region. Beijing has been equally stepping up incursions into Taiwan’s air defence identification zone and military drills around the island, increasing pressure on Taipei.[13]
  • The fact that China leverages coercive maritime activity against the Philippines indicates that Beijing’s attempts to subjugate Manila in the SCS through other means are not producing the expected outcomes.
  • The existence of the US-Philippine alliance may be regarded as a hitherto effective deterrent against any Chinese attack with direct military force on the Philippines. However, further enhanced cooperation with the US and Japan is key to warding off Chinese coercion.

EU lawmakers should not view the SCS incidents and disputes as having solely regional implications. With around 40% of the EU’s foreign trade passing through the South China Sea, EU member states ought to closely monitor Chinese activity and collaborate with their Indo-Pacific partners to safeguard stability. Any uncontrolled escalation of tensions could detrimentally impact the EU economy.[14]


Author: Jakub Witczak – external contributor, Associate at the Boym Institute

[1] “China’s Maritime Disputes”, Council on Foreign Relations,

[2] Ankit Panda, „International Court Issues Unanimous Award in Philippines v. China Case on South China Sea”, The Diplomat, July 12, 2016,

[3] The ship was first used by the US during WWII, later by South Vietnam and eventually by the Philippines.

[4] Agence France-Presse, “Why is a rusty old Philippine warship involved in the South China Sea dispute?”, South China Morning Post, August 8, 2023,

[5] Regine Cabato, “Rising Philippines-China tensions in South China Sea: 5 moments from 2023”, The Washington Post, December 11, 2023,

[6] Caitlin Campbell, Ben Dolven, Thomas Lum, „China-Philippines Tensions in the South China Sea”, Congressional Research Service, January 23, 2024, p. 1,

[7] James Legge, Lucas Lilieholm, Josh Campbell, Chris Lau, „China coast guard water-cannons Philippine ship days after US backs Manila in disputed sea”, CNN, March 23, 2024,

[8] Dean Cheng, Carla Freeman, Brian Harding, Andrew Scobell, „Are China and the Philippines on a Collision Course?”, United States Institute of Peace, March 14, 2024,

[9] Justin Baquisal, „Flexible Enmeshment: The Philippines’ New Approach to China-US Competition”, The Diplomat, February 6, 2023,

[10] Agence France-Press, „US gets access to 4 more Philippine bases amid China military moves”, South China Morning Post, February 2, 2023,

[11] Derek Grossman, „CHINA’S GRAY-ZONE TACTICS SHOW THE U.S.-PHILIPPINE ALLIANCE IS WORKING”, War on the Rocks, November 7, 2023,

[12] Sebastian Strangio, “Philippines to Hold Joint Maritime Patrols With US, Japan”, The Diplomat, April 2, 2024,

[13] Kathrin Hille, Demetri Sevastopulo, „How China’s military is slowly squeezing Taiwan”, Financial Times, July 24, 2023,

[14] Vera Kranenburg, Nick Bontenbal, “RISING SOUTH CHINA SEA TENSIONS AND CONCERNS FOR EUROPE”, Clingendael Institute, August 23, 2023,