In 2025, strategic competition in the South China Sea over sovereignty claims, maritime jurisdiction, and military activities intensified markedly. Frictions at sea and in the air became more frequent and risk-prone. As the Philippines repeatedly entered waters and airspace around China’s Huangyan Dao (Scarborough Shoal), Ren’ai Jiao (Second Thomas Shoal), Xianbin Jiao (Sabina Shoal), and other features—including intrusions into lagoons, territorial seas and airspace—China correspondingly strengthened law enforcement at sea to firmly safeguard national sovereignty, security, and maritime order. Meanwhile, extra-regional actors such as the United States, Japan, and Australia continued to deepen their involvement through patrols, exercises, and more routine force deployments, further highlighting the spillover and internationalization of the South China Sea issue.

Below is a chronological compilation of key events that shaped the South China Sea security environment from January to June  2025, for reference.

January

· Early January: The USS Carl Vinson aircraft carrier strike group operated in the South China Sea.

· Jan 7-11: The China Coast Guard and the Indonesian Coast Guard held their first high-level meeting, exchanging views on practical cooperation such as regular meetings, ship visits, and capacity building.

· Jan 10: The Philippines announced that three construction projects on features it occupies in the Spratly Islands (an airport on Thitu Island and the expansion of two shelters/harbors) are expected to break ground in 2025; PHP 3.03 billion was allocated in the 2025 national budget.

· Jan 8-11: The U.S. and Canadian navies conducted the joint exercise “Noble Wolverine” in the South China Sea.

· Jan 16: China and the Philippines held the 10th meeting of the Bilateral Consultation Mechanism on the South China Sea, agreeing to strengthen dialogue and communication, properly handle maritime differences, and continue practical cooperation in areas including coast guard affairs, marine science and technology, and environmental protection.

· Jan 16-20: France’s aircraft carrier Charles de Gaulle operated in the Strait of Malacca and conducted exercises separately with Malaysia and Singapore.

· Jan 17: Three Philippine warships patrolled near Scarborough Shoal and conducted a unilateral exercise.

· Jan 17-18: The Philippine and U.S. navies conducted bilateral maritime cooperative activities in the South China Sea with the USS Carl Vinson carrier strike group.

· Jan 17-18: The PLA Southern Theater Command organized joint sea-air combat patrols in the South China Sea to safeguard regional peace and stability.

· Jan 21: The French carrier strike group exercised with naval vessels from India, Australia, Canada, the United Kingdom and the United States in the Lombok Strait area of Indonesia.

· Jan 24: Philippine government vessels 3003 and 3004, without China’s authorization, intruded into waters near Tiexian Jiao (Sandy Cay) in the Spratly Islands, attempting to land illegally and collect sand samples; the China Coast Guard lawfully intercepted, controlled, warned and expelled the vessels.

· Jan 24: With China’s approval, the Philippines dispatched a civilian vessel to deliver daily supplies to its illegally grounded warship at Second Thomas Shoal; the China Coast Guard verified the cargo and monitored the vessel throughout the transit.

· Jan 24: The Japan Coast Guard and Indonesia’s maritime security agency conducted a joint exercise off Jakarta.

· Jan 27-31: After three weeks of operations in the South China Sea, the USS Carl Vinson arrived at Laem Chabang, Thailand, for a port call; the French carrier strike group conducted operations in waters off Bali.

· Jan 31: The PLA Southern Theater Command organized sea and air forces to conduct combat readiness patrols in the territorial waters and airspace of Scarborough Shoal and surrounding areas; since January the theater has strengthened patrols and control to resolutely defend sovereignty and security and maintain peace and stability.

· Jan 31: The China Coast Guard conducted law-enforcement patrols in the territorial waters of Scarborough Shoal and adjacent areas; since January it has intensified such patrols to strengthen control and safeguard territorial sovereignty and maritime rights and interests.

February

· Feb 1-4: The Royal Canadian Navy frigate HMCS Ottawa visited Sihanoukville, Cambodia.

· Feb 3: The PLA Southern Theater Command organized sea and air forces to conduct training via the Basilan Strait into the far seas; the operations were safe, standardized and professional, fully consistent with international law and practice.

· Feb 3-18: The USS Carl Vinson carrier strike group participated in the “Pacific Starlight” exercise with the French carrier strike group and the Japan Maritime Self-Defense Force in the South China Sea and the Philippine Sea.

· Feb 4: The Philippine and U.S. air forces conducted a joint patrol near Scarborough Shoal; two Philippine FA-50 fighters and two U.S. B-1B bombers took part.

· Feb 4: The PLA Southern Theater Command Air Force conducted a routine patrol in the airspace around Scarborough Shoal.

· Feb 5: Australia, Japan, the Philippines and the United States conducted multilateral maritime cooperative activities in the South China Sea.

· Feb 5: The PLA Southern Theater Command conducted a routine patrol in the South China Sea.

· Feb 6: China and Brunei issued a joint statement agreeing to support enterprises of both countries in pursuing cooperation in offshore oil and gas on a commercial basis, including resource development in mutually agreed areas.

· Feb 7-11: HMCS Ottawa visited the Philippines.

· Early February: JMSDF destroyer Akizuki transited the Taiwan Strait.

· Feb 10-12: U.S. Navy destroyer USS Johnson and survey ship USNS Bowditch transited the Taiwan Strait; the PLA Eastern Theater Command monitored and tracked the transit throughout and responded effectively.

· Feb 11: An Australian military aircraft deliberately intruded into the airspace over China’s Xisha (Paracel) Islands without authorization; China took expulsion measures that it said were legitimate, professional and restrained.

· Feb 12: The PLA Southern Theater Command conducted a routine patrol in the South China Sea.

· Feb 13-16: Singapore’s landing ship tank RSS Endeavour visited Manila.

· Feb 16: HMCS Ottawa transited the Taiwan Strait and publicly hyped the transit; the PLA Eastern Theater Command monitored and tracked it throughout and responded effectively.

· Feb 18: A Philippine C-208 aircraft illegally entered China’s airspace over Scarborough Shoal, repeatedly changed altitude, and descended 920 meters in 218 seconds, deliberately crossing near the altitude layer of a Chinese helicopter on routine patrol in an unprofessional and dangerous manner, creating a high risk of an air-sea incident.

· Feb 18: Indonesia hosted Exercise Komodo 2025, with 38 countries and 19 foreign warships participating.

· Feb 20: Two Philippine C-208 aircraft and one N-22 aircraft illegally entered airspace near features of China’s Nansha (Spratly) Islands; the PLA Southern Theater Command tracked the aircraft throughout and warned and expelled them.

· Feb 21: Vietnam’s Ministry of Foreign Affairs issued a statement on baselines for the territorial sea in the Gulf of Tonkin.

· Feb 21: China and ASEAN countries held the 23rd Senior Officials’ Meeting on the implementation of the Declaration on the Conduct of Parties in the South China Sea (DOC).

· Feb 22-23: China and ASEAN countries held the 46th Joint Working Group Meeting on the implementation of the DOC.

· Feb 27: The PLA Southern Theater Command conducted combat readiness patrols in the territorial waters and airspace of Scarborough Shoal and surrounding areas; since February it has strengthened patrols and control to defend sovereignty and maintain peace and stability.

· Feb 27: The China Coast Guard conducted law-enforcement patrols around Scarborough Shoal; since February it has stepped up patrols and organized routine sea-air integrated control, including tracking, warnings, expulsion, boarding inspections and detention, to strengthen maritime management and control.

· Feb 27: The China Coast Guard and Vietnam Coast Guard conducted the first joint patrol of 2025 in the northern waters of the Beibu Gulf. Since 2024, the two sides have carried out one joint patrol per quarter in border waters.

March

· Mar 1: French Navy frigate Provence visited Lotus Port, Ho Chi Minh City, Vietnam.

· Mar 4: With China’s approval, the Philippines sent a civilian vessel to deliver daily supplies to its illegally grounded warship at Second Thomas Shoal; the China Coast Guard verified and monitored the vessel throughout.

· Mar 6: France’s Charles de Gaulle carrier strike group visited Singapore’s Changi Naval Base; the French fleet also visited the Philippines, Indonesia and Malaysia.

· Mar 7: Wang Yi elaborated China’s position on the South China Sea. China and Indonesia signed an intergovernmental consensus document on maritime joint development. China and Malaysia launched a bilateral dialogue on maritime issues. China said it has achieved full coverage of institutionalized maritime dialogue mechanisms with all South China Sea parties concerned. Under China’s impetus, negotiations on the COC accelerated and completed a third reading of the draft.

· Mar 15: The Philippine Department of Environment and Natural Resources said it would conduct an integrated biodiversity protection research program in April at Reed Bank and Commodore Reef in the Spratly Islands.

· Mar 27: The United States, the Philippines and Japan conducted a joint patrol near Scarborough Shoal; a PLA Navy vessel monitored the activity.

· Mar 28: The PLA Southern Theater Command conducted a routine patrol in the South China Sea, criticizing the Philippines for organizing so-called “joint patrols” with extra-regional countries to spread unlawful claims and create instability.

April

· Apr 2: The U.S. State Department said it had approved a potential USD 5.58 billion sale to the Philippines of 20 F-16 fighter aircraft and related equipment.

· Apr 2-3: The two militaries held the 2025 China-U.S. Maritime Military Consultative Agreement (MMCA) working group meeting in Shanghai, exchanging views on the sea-air security situation, assessing implementation of the Rules of Behavior for Safety of Air and Maritime Encounters, and discussing measures to improve maritime military safety.

· Apr 2-6: Royal Thai Navy frigate HTMS Naresuan visited Vietnam’s Naval Region 5.

· Apr 6: A China Coast Guard vessel intercepted a Philippine patrol vessel at Scarborough Shoal.

· Apr 8: The Philippine and U.S. air forces launched the “Cope Thunder” joint exercise.

· Apr 8: Australia donated 20 drones to the Philippine Coast Guard.

· Apr 9: U.S. Navy littoral combat ship USS Savannah conducted a sailing operation in the South China Sea.

· Apr 9: With China’s approval, the Philippines sent a civilian vessel to deliver supplies to its illegally grounded warship at Second Thomas Shoal; the China Coast Guard verified and monitored the vessel throughout.

· Apr 9-11: The Philippines hosted a new round of ASEAN-China COC negotiations, continuing to process paragraphs of the draft text.

· Mid-April: China Coast Guard officers boarded and inspected Tiexian Jiao (Sandy Cay) in the Spratlys, collected video evidence of alleged Philippine illegal activities, displayed China’s national flag to assert sovereignty, and cleared plastic bottles, wooden sticks and other debris left on the reef.

· Apr 14-17: Philippine Coast Guard ship Gabriela Silang visited Da Nang, Vietnam.

· Apr 14-15: President Xi Jinping paid a state visit to Vietnam; the joint statement stressed better control and active resolution of maritime differences, jointly maintaining peace and stability in the South China Sea, advancing consultations on maritime joint development and on delimitation outside the mouth of the Beibu Gulf, and expanding low-sensitivity maritime cooperation including search and rescue.

· Apr 14: A China Coast Guard vessel (21612) collided with the Philippine patrol boat Cabra (4409) about 36 nautical miles south of Scarborough Shoal. China said the Philippine vessel suddenly and dangerously cut across the CCG ship’s bow four times without warning, threatening the safety of personnel and vessels.

· Apr 16-17: The Chinese and Vietnamese navies carried out their 38th joint patrol in the Beibu Gulf, each side dispatching two naval vessels (four in total).

· Apr 17: President Xi Jinping paid a state visit to Malaysia; the joint statement emphasized the importance of peace, security and stability in the South China Sea, agreed to resolve disputes peacefully through friendly consultations in accordance with international law, and aimed to conclude an effective, substantive COC by 2026.

· Apr 19: JMSDF minesweeper tender Bungo and minesweeper Etajima visited Cambodia’s Ream Naval Base.

· Apr 20: Philippine Patrol Vessel 36 illegally entered China’s territorial sea around Scarborough Shoal without approval; the PLA Southern Theater Command Navy tracked, monitored, warned and expelled it in accordance with law.

· Apr 21: The first ministerial meeting of the China-Indonesia “2+2” foreign and defense ministers’ dialogue was held in Beijing. The two sides committed to strengthening maritime cooperation to promote South China Sea security; the two coast guards signed a memorandum of understanding on maritime security.

· Apr 21-May 9: The annual U.S.-Philippines “Balikatan” exercise began, held at locations close to the South China Sea and Taiwan.

· Apr 22-24: China Coast Guard and Vietnam Coast Guard (two vessels each) conducted the first joint patrol of 2025 in the Beibu Gulf.

· Apr 23: U.S. Navy destroyer USS Lawrence transited the Taiwan Strait and publicly hyped the transit; the PLA Eastern Theater Command monitored and tracked it throughout and handled it effectively in accordance with law.

· Apr 23: The United States deployed a U.S. Marine Corps expeditionary ship interdiction system (NMESIS) to the Philippines as part of Balikatan.

· Apr 23: India delivered the second batch of BrahMos supersonic cruise missiles to the Philippines, the second of three batches under the bilateral agreement.

· Apr 25: China’s Ministry of Natural Resources and other agencies released the Investigation Report on the Coral Reef Ecosystems of Tiexian Jiao and Niue Jiao, providing the first comprehensive and systematic assessment of those reef ecosystems.

· Apr 27: Six Philippine personnel illegally landed on Tiexian Jiao; China Coast Guard law-enforcement personnel boarded the reef and handled the case in accordance with law.

· Apr 29: The PLA Southern Theater Command conducted a routine patrol in the South China Sea, saying it tracked and monitored Philippine provocations and so-called joint patrols with extra-regional countries.

· Apr 30: The China Coast Guard conducted law-enforcement patrols in the territorial waters of Scarborough Shoal and nearby areas; since April it has strengthened tracking, warnings and expulsion to reinforce maritime control and safeguard sovereignty and maritime rights.

· Apr 30: The Philippines and New Zealand signed a Status of Visiting Forces Agreement.

May

· May 4: Under the Five Power Defence Arrangements (FPDA), the United Kingdom, Australia, Malaysia, New Zealand and Singapore held Exercise “Bersama Shield 25” in the South China Sea.

· May 5: A Philippine patrol craft attempted to intrude into China’s territorial sea around Scarborough Shoal; the PLA Southern Theater Command organized sea and air forces to track, monitor, warn and expel it, preventing entry. China said the on-scene actions were professional, standardized and lawful.

· May 9-16: China and Singapore held the “China-Singapore Cooperation-2025” maritime joint exercise in Singapore, with four vessels participating.

· May 10-14: A Russian Navy task group visited Da Nang, Vietnam (Tien Sa Port).

· May 11: Russia transferred to Vietnam an assisted scientific research ship, Professor Gagarinskiy.

· May 12: U.S. Navy destroyer USS Curtis Wilbur conducted flight operations in the South China Sea.

· May 14-15: The Chinese and Singaporean navies conducted the “Maritime Cooperation 2025” live-force drill in the South China Sea.

· May 14-28: The Chinese and Cambodian militaries held the “Golden Dragon-2025” joint exercise near Kampong Chhnang Province and in waters/airspace near Sihanoukville.

· May 14: The Philippines and Germany signed a defense cooperation agreement to expand bilateral defense cooperation.

· May 15: Vietnam’s Ministry of Foreign Affairs protested China’s fishing moratorium in the South China Sea.

· May 16: With China’s approval, the Philippines sent a civilian vessel to deliver daily supplies to its illegally grounded warship at Second Thomas Shoal; the China Coast Guard verified and monitored the vessel throughout.

· May 16-20: The U.S. Coast Guard cutter Stratton visited Palawan, Philippines.

· May 17: Royal Navy offshore patrol vessel HMS Spey conducted a freedom of navigation operation in the South China Sea.

· May 20: The Philippines and the United States conducted joint exercises in the South China Sea involving their navies, air forces and coast guards.

· May 20: The Philippines commissioned its most advanced missile frigate BRP Miguel Malvar (FFG-06).

· May 21: Philippine government vessels 3002 and 3003 illegally entered waters near Zhubi Jiao (Subi Reef) and Tiexian Jiao and landed personnel on Tiexian Jiao. China Coast Guard officers took control measures and boarded the reef to investigate and handle the case. Vessel 3002 dangerously approached China Coast Guard ship 21559, causing a scrape; the CCG used warning water cannons.

· May 25-30: China Coast Guard ship 3306 and vessel 21549 tracked and monitored throughout the voyage the Philippine group vessel Captain Felix Oca heading to Thitu Island.

· May 26: The live-force phase of the China-Cambodia “Golden Dragon-2025” exercise was held near Sihanoukville, with 11 naval vessels and three air force helicopters participating.

· May 27: The USS Nimitz carrier strike group entered the South China Sea.

· May 31: The PLA Southern Theater Command conducted combat readiness patrols around Scarborough Shoal; since May it has strengthened patrols and vigilance to defend sovereignty and maintain regional peace and stability.

· May 31: The China Coast Guard conducted law-enforcement patrols around Scarborough Shoal; since May it has strengthened tracking, warnings and expulsion to reinforce maritime control and safeguard sovereignty and maritime rights.

June

· Jun 3-5: PLA Navy ship Changbai Shan made a technical port call in Brunei.

· Jun 4: The Philippines announced completion of the runway extension project on Thitu Island and said it is building hangars and a control tower on the island.

· Jun 4: The Philippines and the United States held the 7th Maritime Cooperative Activity (MCA) in the South China Sea.

· Jun 5: The Philippines and South Korea signed a USD 700 million agreement to procure 12 FA-50 fighter aircraft.

· Jun 6: Japan’s House of Councillors approved the Japan-Philippines Reciprocal Access Agreement (RAA), making the Philippines the third country after Australia and the UK to sign such an agreement with Japan.

· Jun 14: Philippine and Japanese naval vessels conducted an MCA in the South China Sea (a joint anti-submarine exercise).

· Jun 14: The PLA Southern Theater Command organized a joint sea-air patrol in the South China Sea, criticizing the Philippines for organizing so-called joint patrols with extra-regional countries and raising security risks.

· Jun 15-18: The Philippines organized multiple vessels to conduct illegal activities in waters adjacent to Ban Yue Jiao (Half Moon Shoal) and Jianzhang Jiao (Commodore Reef) in the Nansha; the China Coast Guard handled the situation in accordance with law. China said Philippine vessels used a “protecting fishermen” pretext to infringe and provoke, undermining stability.

· Jun 16: The U.S. Congress considered establishing ammunition production and storage facilities at Subic Bay, Philippines.

· Jun 16-20: Malaysia Maritime Enforcement Agency vessel 8305 visited Sanya, Hainan, China.

· Jun 18: China and Malaysia held their first coast guard working meeting, exchanging views on personnel exchanges, information sharing, maritime search and rescue, and joint law enforcement, and agreeing to deepen practical cooperation and manage maritime contingencies together.

· Jun 18: HMS Spey transited the Taiwan Strait.

· Jun 20: Philippine government vessel 3006 approached and intruded toward China’s territorial sea around Scarborough Shoal; the China Coast Guard used warnings, shadowing and maneuvering pressure, and water-cannon warnings to expel it.

· Jun 24: UK and Australian naval vessels conducted a joint freedom of navigation operation in waters of the Nansha in the South China Sea.

· Jun 26: The China Coast Guard and military forces conducted what was described as the largest rescue drill in recent years in the South China Sea near Yongxing Dao (Woody Island), involving over 200 personnel, 15 vessels and two rescue helicopters.

· Jun 30: The China Coast Guard conducted law-enforcement patrols around Scarborough Shoal; since June it has strengthened tracking, warnings and expulsion to reinforce maritime control and safeguard sovereignty and maritime rights.

· Jun 30: PLA Navy aircraft carrier groups Liaoning and Shandong completed far-seas, combat-oriented training, deploying into the western Pacific and conducting opposing-force drills and multiple subjects including ISR and warning, strike/counterstrike, anti-surface attack, air defense, and day-night carrier aviation operations.