Four major developments shaped the security environment in the South China Sea in 2024: (1) increased Chinese coercion against Philippine naval vessels and aircraft; (2) adoption of a new maritime defense strategy by the Philippines; (3) Vietnam’s stepped-up construction activities in the Spratly Islands; and (4) slow progress in negotiations on a Code of Conduct (COC).
Chinese Coercion
In 2024, China markedly stepped up its intimidation, harassment, and coercion against Philippine Navy, Philippine Coast Guard (PCG), and civilian vessels and aircraft operating legally in the Philippines’ Exclusive Economic Zone (EEZ). China also perfected the art of surging large numbers of People’s Liberation Army Navy (PLAN), China Coast Guard (CCG), China Maritime Militia (CMM) vessels into the West Philippine Sea (the name in the Philippines for the parts of the South China Sea within Manila’s EEZ). The highest surge totaled 207 Chinese vessels of all types on September 10, following the confrontation at Sabina Shoal discussed below.
In addition, China resorted to lawfare in passing legislation, such as the Provisions on Administrative Enforcement Procedures for Coast Guard Agencies (enacted May 15), to give it ostensible legal cover to detain foreign vessels in “waters under Chinese jurisdiction.” In November, China issued the coordinates for baselines around Huangyan Dao (the Chinese name for Scarborough Shoal) and deposited a copy with the United Nations.
From February to June, a combination of CCG and CMM vessels repeatedly confronted Philippine efforts to resupply its military forces on the BRP Sierra Madre, an old naval vessel grounded on Second Thomas Shoal. Chinese intimidation and coercion ranged from dangerous maneuvering, deliberate ramming, and the use of high-powered water cannons.
On June 17, Chinese vessels conducted their most violent confrontation of a Philippine rotation and resupply (RORE) mission. Chinese sailors armed with axes, pikes, and knives towed away a Filipino Rigid Hull Inflatable Boat. The Chinese sailors then boarded the boat and physically assaulted Philippine marines, smashed their communication equipment, confiscated their weapons, and punctured the hull. In another incident, a Filipino marine had his thumb severed when a Chinese steel hulled boat rammed into his craft moored alongside the BRP Sierra Madre. On June 30, China accosted a PCG ship, the Malabrigo, at Second Thomas Shoal.
The June 17 incident marked an inflection point. On July 2, the Ninth Philippine-China Bilateral Consultation Mechanism on the South China Sea met in Manila. The two sides agreed to establish a hotline. After a series of discussions, on July 21 the two sides reached an unpublicized provisional agreement to prevent similar incidents.
At the same time, General Romeo Brawner, chief of the Armed Force of the Philippines, in reference to China’s grey zone tactics characterized them with the pithy acronym ICAD – illegal, coercive, aggressive and deceptive – tactics.
On July 27, the Philippines’ ML Lapu-Lapu resumed a RORE mission without major incident, setting a precedent for the remainder of the year. However, each RORE mission led to an exchange of words as China claimed that it had been given advanced notification and had ensured that only humanitarian supplies were involved. The Philippines denied the Chinese accounts and claimed that the provisional agreement “did not prejudice each other’s position in the South China Sea.” In December, the Philippines successfully conducted its last RORE mission of the year to Second Thomas Shoal without incident.
Hopes that the provisional agreement could be extended across the West Philippine Sea were dashed when Sabina and Scarborough Shoals became the sites for Chinese coercion against the Philippines.
In April, after the discovery of crushed coral at Sabina Shoal, the Philippines deployed its largest Coast Guard vessel, the BRP Teresa Magbanua, to pre-empt Chinese occupation and construction on the shoal. In May, the Philippines dispatched the BRP Cabra and BRP Malabrigo to take up station alongside the BRP Teresa Magbanua. China responded by deploying a PLAN Landing Platform Dock and a PLAN Landing Helicopter Dock to conduct amphibious exercises around Sabina.
On August 18, BRP Cabra and BRP Engaño, two PCG patrol boats providing supplies to Patag and Lawak islands, were rammed by CCG vessels in separate incidents. Both PCG boats sustained structural damage. On August 25, eight PLAN and CCG ships disrupted the Bureau of Fisheries and Aquatic Resources (BFAR) BRP Datu Sanday on a resupply mission to Sabina and Half Moon Shoal by firing water cannons and ramming.
On August 19, 40 PLAN, CCG, and CMM vessels blocked the BRP Cabra and BRP Engaño from resupplying the BRP Teresa Magbanua. The Philippines responded by sending a helicopter to replenish dwindling supplies. China countered by blockading the BRP Teresa Magbanua and ramming its hull on three occasions.
On September 12, the BRP Teresa Magbanuay withdrew from Sabina Shoal due to bad weather, a shortage of rations, medical treatment needed for sick crew, and the need for repairs to its bridge and freeboard.
Scarborough Shoal became the third site of contention as CCG ships harassed maritime patrols by the Philippine Air Force and the BFAR. There were three aerial incidents in August during which Chinese military aircraft fired flares in the paths of a Philippine Air Force and BFAR patrol aircraft. On August 19, it was reported that the Philippines had filed 40 diplomatic protests with China during the year to that point, protesting violations of its sovereignty.
In early December, a CCG vessel fired its high-pressure water cannon at a BFAR boat carrying supplies to Filipino fisherman at Scarborough Shoal. Later in the month, Chinese jet fighters and bombers and naval forces conducted “combat readiness patrols” around Scarborough Shoal. China also dispatched its 12,000-ton “monster” Coast Guard ship 5901 to Scarborough Shoal to join three CCG and seven CMM ships already stationed there.
In this photo provided by the Philippine Coast Guard, a China Coast Guard vessel fires a water cannon at a Philippine boat near Bajo de Masinloc, Dec. 3, 2024.
The Philippines’ Comprehensive Archipelagic Defense Concept
In response to a rise in Chinese coercive actions in 2023, in January 2024 the Philippines announced a whole-of-government Comprehensive Archipelagic Defense Concept (CADC). According to Brawner, the AFP chief, the Philippines was pursuing a three-pronged maritime defense strategy involving establishing an effective presence; creating an effective deterrence by modernizing military equipment; and leveraging alliances and partnerships.
The CADC involved repositioning resources, combined civil-military air and sea patrols to monitor Chinese incursions, resupplying Filipino fishermen, assertive transparency in publicizing incidents, and upgrading of infrastructure on Palawan and other land features in the West Philippine Sea.
In addition, President Ferdinand Marcos, Jr. approved the Re-Horizon-3 program, valued at $35 billion over the next decade, to modernize the Armed Forces of the Philippines.
The Philippines also used international law to bolster its sovereign jurisdiction in the West Philippine Sea. In June, for example, the Philippines submitted a claim for an extended continental shelf to the United Nations Commission on the Limits of the Continental Shelf. In November, Marcos responded to China’s use of lawfare by signing into law the Philippines Maritime Zone Act and the Philippine Archipelagic Sea Lanes Act.
The Philippines also participated in bi- and multilateral land, sea, and air military exercises with the United States, Australia, and Japan that were joined by other security partners. The Philippines and the United States conducted the largest Exercise Balikatan in its history. Philippine Marines journeyed to Japan to participate in Exercise Yama Sakura as observers for the first time.
As a result of Chinese coercion at Second Thomas Shoal, the United States on several occasions offered to assist in resupply. The Philippines declined the offer, stating that they “will exhaust all means before seeking foreign intervention.” Philippines officials, however, did raise the possibility of whether there should be consultations with the United States to consider revising Article 4 of the Mutual Defense Treaty to better define what was meant by an “armed attack” in light of the June 17 incident.
In a notable development, the Philippines permitted the deployment of the U.S. Typhon Mid-Range Capability (MRC) system in April during Exercise Salaknib. The Typhon system can fire the SM-6 missile with a maximum range of 500 km or the Tomahawk cruise missile with a range of 1,300 to 2,500 km depending on the variant. The SM-6 can cover the Philippines’ Exclusive Economic Zone and China’s “big three” military bases on Fiery Cross, Mischief, and Subi reefs. Philippine defense officials indicated that they would like to procure the Typhon system and declined to confirm if the U.S. Typhon MRC system would be withdrawn. China protested vehemently and declared that relations with the Philippines were at a crossroad. However, as of late January 2025, the Typhon missiles are still in the Philippines, with no plans to remove it.
In November, during a visit to the Philippines by then-U.S. Secretary of Defense Lloyd Austin, he revealed that U.S. military personnel assigned to Task Force Ayungin had been deployed to Palawan island to assist the Philippines in logistics and maritime domain awareness.
Vietnamese Construction in the Spratlys
During 2024, all was relatively quiet on Vietnam’s eastern front in the East Sea (Vietnam’s name for its area of the South China Sea). Chinese survey ships and aircraft, including a drone, flew through the airspace above Vietnam’s EEZ on several occasions. There were at least two incidents in which China Coast Guard personnel boarded Vietnamese fishing craft and assaulted the crew, smashed communication and navigation equipment, and confiscated their fish catch.
In June, the Asia Maritime Transparency Initiative reported that Vietnam had stepped up construction on its 27 land features in the Spratly Islands through land fill, dredging harbors, and constructing infrastructure, including a 1,050 meter-long airfield on Barque Canada. Unlike China’s propaganda barrage against the Philippines, China remained silent on Vietnam’s activities. However, South China Sea issues were raised when party leaders Xi Jinping and To Lam met in Beijing in August 2024.
South China Sea Code of Conduct
In July 2023, under Indonesia’s chairmanship, ASEAN members and China adopted the Guidelines for Accelerating the Early Conclusion of an Effective and Substantive Code of Conduct in the South China Sea. There was a glimmer of optimism when it was announced in October that ASEAN members and China would commence the third and final reading of the Single Draft South China Sea Code of Conduct Negotiating Text.
Laos replaced Indonesia as ASEAN chair in 2024. On July 25, at the annual ASEAN Ministerial Meeting in Vientiane, it was reported that Cambodia and Laos blocked a proposal by the Philippines to include a reference to the June 17 incident. By year’s end various ASEAN diplomats privately reported that little progress had been made on the third reading of the COC because of divisions within ASEAN.
Conclusion
Major developments in the South China Sea in 2024 do not augur well for 2025. China will remain committed to asserting its sovereignty over land features and adjacent waters that lie within the Philippines’ Exclusive Economic Zone, and the PLAN and CCG continue to expand in numbers. China will continue to pressure the Philippines to convince it that resistance is futile because the Trump administration will be a fickle ally and the Philippines lacks the capacity to stand alone against China.
The Philippines will have to weather the uncertainty of the U.S. commitment to the Mutual Defense Treaty now that President Donald Trump has taken office. Pete Hegseth, Trump’s secretary of defense, admitted he didn’t know which countries were members of ASEAN when questioned at his confirmation hearing. When Hegseth tried to make up for this lapse by noting he knew the U.S. had alliances with Japan, South Korea and Australia, he failed to mention the Philippines. Also, Marcos was not invited to Trump’s inauguration (while Xi Jinping was, although he sent China’s vice president in his stead).
Vietnam will continue to build infrastructure on its land features in the Spratly islands. It is unclear, however, if Vietnam will construct more air strips and militarize these features. This could provoke China into ending its “softly, softly” approach.
Malaysia has replaced Laos as ASEAN chair and this has given rise to guarded optimism that progress can be made on the South China Sea Code of Conduct in 2025. China can be expected to press for a quick conclusion to negotiations on the Code of Conduct with ASEAN members as one means of undermining a U.S. security role in maritime affairs.