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 July to December 2025, for reference.

July

· Jul 3: The PLA Southern Theater Command conducted combat readiness patrols around Scarborough Shoal; since June it has strengthened patrols and vigilance to defend sovereignty and maintain regional peace and stability.

· Jul 3-7: PLA Navy aircraft carrier Shandong and accompanying destroyers Yan’an and Zhanjiang and frigate Yuncheng visited Hong Kong.

· Jul 5: PLA Navy hospital ship “Silk Road Ark” completed its “Health Delivery to the Maritime Frontier” mission: 17 days and over 2,200 nautical miles, providing medical services focused on training injury prevention and psychological health, with over 3,000 consultations and more than 100 surgeries.

· Jul 4-7: The U.S. aircraft carrier George Washington made a port call in Manila, Philippines.

· Jul 7-18: The United States and the Philippines held the “Cope Thunder” joint air exercise; the U.S. for the first time deployed F-35 fighters to the Philippines.

· Jul 11: Australia announced assistance to the Philippine Coast Guard worth PHP 110 million  in drones and maritime domain awareness technologies.

· Jul 13: China’s Foreign Ministry spokesperson responded to the Philippines’ statement marking the ninth anniversary of the South China Sea arbitration award, reiterating that the “award” is illegal, invalid and non-binding, and that China does not accept or recognize it nor any claims or actions based on it; China said its territorial sovereignty and maritime rights in the South China Sea are not affected by the award under any circumstances.

· Jul 15: France and the Philippines held negotiations on a Visiting Forces Agreement.

· Jul 16: The Philippines and the United States conducted the 8th MCA / maritime exercise.

· Jul 16: The USS Carl Vinson carrier strike group transited the Strait of Malacca into the South China Sea.

· Jul 24-27: Indian Navy guided-missile destroyer INS Delhi visited Da Nang, Vietnam.

· Jul 29: The Royal Malaysian Navy held Exercise TAMING SARI 23/25 in the South China Sea with 15 vessels and two submarines, firing several Exocet missiles and one Black Shark torpedo.

· Jul 29: The PLA Southern Theater Command conducted combat readiness patrols around Scarborough Shoal; since July it has strengthened patrols and vigilance to defend sovereignty and maintain regional peace and stability.

· Jul 30: An Indian Navy task group made a port call in Manila; India and the Philippines conducted their first joint patrol in the South China Sea.

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

August

· Aug 3: The Philippine and Indian navies conducted their first joint patrol in the South China Sea.

· Aug 3-4: The PLA Southern Theater Command Navy conducted a routine patrol in the South China Sea, criticizing the Philippines for organizing so-called joint patrols with extra-regional countries and undermining peace and stability.

· Aug 6: China intercepted a Philippine Bureau of Fisheries and Aquatic Resources (BFAR) vessel near Dunqian Sandbank in the Spratlys.

· Aug 8: Philippine President Ferdinand Marcos Jr. said the Philippines would, during its ASEAN chairmanship next year, work to facilitate adoption of a legally binding COC.

· Aug 11: Multiple Philippine coast guard and government vessels intruded into the territorial sea of Scarborough Shoal, while a Philippine military aircraft entered Scarborough Shoal’s airspace. The China Coast Guard used tracking, maneuvering pressure, interception and control measures to expel the vessels. (Foreign media reported that a China Coast Guard vessel and a PLA Navy destroyer collided during interception operations in the Scarborough Shoal area.)

· Aug 11-13: China and ASEAN countries held the 48th Joint Working Group Meeting on the implementation of the DOC.

· Aug 13: U.S. Navy destroyer USS Higgins entered China’s territorial sea around Scarborough Shoal without authorization; the PLA Southern Theater Command dispatched naval forces to track, monitor, warn and expel the vessel in accordance with law.

· Aug 13: A Chinese fighter aircraft intercepted a Philippine coast guard aircraft while on patrol over Scarborough Shoal.

· Aug 14: China and ASEAN countries held the 24th Senior Officials’ Meeting on the implementation of the DOC in Malaysia.

· Aug 15: Australia and the Philippines conducted their largest-ever “Wave” joint exercise.

· Aug 19: Naval vessels from the Philippines, Australia and Canada conducted a joint sail in the South China Sea.

· Aug 19: The Philippine warship illegally grounded at Second Thomas Shoal (57) released two small boats that ignored repeated warnings and approached a China Coast Guard vessel in an unprofessional and dangerous manner in a deliberate “collision scam” provocation; the CCG took control measures in accordance with law.

· Aug 22: U.S. and Philippine defense officials said the two militaries would conduct over 500 military cooperation activities (exercises) in 2026.

· Aug 23: The armed forces of the Philippines, Australia and Canada conducted joint exercises in the South China Sea.

· Aug 27: Australian, Canadian and Philippine naval vessels and aircraft held the ALON 2025 air-defense exercise east of Scarborough Shoal.

· Aug 29: The PLA Southern Theater Command conducted combat readiness patrols around Scarborough Shoal; since August it has strengthened patrols and control to respond to infringements and provocations and to defend sovereignty and maintain regional peace and stability.

· Aug 29: The China Coast Guard conducted law-enforcement patrols around Scarborough Shoal; since August it has strengthened tracking, warnings and expulsion to reinforce maritime control and safeguard sovereignty and maritime rights.

September

· Sep 3: The United States, Australia, Canada and the Philippines conducted a multilateral MCA in the South China Sea.

· Sep 3: The PLA Southern Theater Command Navy conducted a routine patrol in the South China Sea, criticizing the Philippines for organizing so-called joint patrols with extra-regional countries and undermining peace and stability.

· Sep 5: The Philippine military delivered food, fuel and replacement personnel to the warship illegally grounded at Second Thomas Shoal; the previous resupply was in July. The same day, two U.S. Navy destroyers patrolled in the South China Sea.

· Sep 6: Canadian frigate HMCS Québec and Australian destroyer HMAS Brisbane transited the Taiwan Strait and conducted disruptive provocations; the PLA Eastern Theater Command monitored and tracked them throughout and responded effectively.

· Sep 10: China’s State Council approved the establishment of the Scarborough Shoal National Nature Reserve. The National Forestry and Grassland Administration announced its area, scope and functional zoning. The reserve is located in Sansha City, Hainan Province, covering 3,523.67 hectares, with coral reef ecosystems as the main protected object.

· Sep 11: The Japan-Philippines Reciprocal Access Agreement (RAA) entered into force. Japan previously pledged support for modernization of the Philippine Coast Guard, signed an Official Security Assistance agreement in December last year (JPY 1.6 billion / USD 10.8 million in equipment), joined the U.S.-Philippines Balikatan exercise for the first time in April, and in July proposed transferring six retired Abukuma-class frigates to the Philippines.

· Sep 12-13: The PLA Southern Theater Command conducted routine patrols in the South China Sea, criticizing the Philippines for organizing so-called joint patrols with extra-regional countries and undermining peace and stability.

· Sep 12: U.S. destroyer USS Higgins and UK frigate HMS Richmond transited the Taiwan Strait and conducted disruptive provocations; the PLA Eastern Theater Command monitored and tracked them throughout and responded effectively.

· Sep 15-16: The U.S. Navy and Royal Australian Navy conducted bilateral training in the South China Sea.

· Sep 16: The Philippines organized more than 10 government vessels to intrude illegally into the territorial sea of Scarborough Shoal from multiple directions; the China Coast Guard used measures including warnings, route control and water-cannon spraying. Philippine vessel 3014 deliberately rammed a China Coast Guard ship conducting law-enforcement operations in what China described as an unprofessional and dangerous manner.

· Sep 17: The Philippine Navy conducted a ship-launched missile firing exercise in the South China Sea.

· Sep 20: The UK aircraft carrier strike group centered on HMS Prince of Wales arrived in Singapore after transiting the South China Sea.

· Sep 22: Japan delivered 14 drones and seven rescue boats to Malaysia under its Official Security Assistance program.

· Sep 24: The U.S. Navy Ohio-class nuclear-powered guided-missile submarine USS Ohio deployed to the South China Sea and visited the Philippines.

October

· Oct 1: The PLA Southern Theater Command said that since September it has continuously strengthened combat readiness patrols around Scarborough Shoal, enhancing control and effectively responding to infringements and provocations to defend sovereignty and maintain peace and stability; China Coast Guard patrols around Scarborough Shoal also intensified since September to expel unlawful intrusions and safeguard sovereignty and maritime rights.

· Oct 1: The U.S. Department of Defense approved a contract to upgrade major Philippine Navy bases near the South China Sea to support small craft and unmanned surface vessels.

· Oct 2: Indian Navy frigate INS Sahyadri visited Kemaman, Malaysia, as part of the Eastern Fleet’s deployments in the South China Sea and the Indo-Pacific.

· Oct 6-17: The United States and the Philippines held the “Sama Sama” joint maritime exercise, with ships from the United States, the Philippines and Japan participating.

· Oct 7: The Philippine Coast Guard and BFAR implemented the “New Fishermen Heroes Program,” supplying Philippine fishermen near Scarborough Shoal and Sabina Shoal to support expanded fishing production.

· Oct 8: China announced it would hold the “Shield of Friendship-2025” joint military exercise with Malaysia in the South China Sea, focusing on humanitarian assistance and maritime security.

· Oct 8: The Philippines and France neared conclusion of a Status of Visiting Forces Agreement that would allow joint exercises on each other’s territory.

· Oct 10: The USS Nimitz carrier strike group transited the Singapore Strait into the South China Sea for operations.

· Oct 10: PLA Navy amphibious landing ship Yimeng Shan and training ship Qi Jiguang arrived in Cambodia on a friendly visit.

· Oct 10-14: Royal Australian Navy frigate HMAS Ballarat visited Sihanoukville, Cambodia.

· Oct 12: A Russian Navy task group visited Da Nang, Vietnam.

· Oct 12: Philippine government vessels 3002 and 3003 illegally entered waters near Tiexian Jiao. One vessel dangerously approached a China Coast Guard ship, resulting in a scrape. China said full responsibility lay with the Philippines. At 09:19, vessel 3003 ignored repeated warnings and dangerously approached CCG 21559, causing the collision; the CCG imposed control measures and expelled the vessels.

· Oct 13: The China Coast Guard intercepted Philippine coast guard and government vessels and fishing boats near Scarborough Shoal and used water cannons as a warning.

· Oct 13: A PLA Navy task group arrived at Port Klang, Malaysia, to participate in the China-Malaysia “Peace and Friendship-2025” joint exercise on Oct 19.

· Oct 15: A Chinese helicopter and a J-16 fighter aircraft expelled a Philippine government aircraft over Scarborough Shoal.

· Oct 16: Two Philippine reconnaissance aircraft illegally entered the airspace over Scarborough Shoal; the China Coast Guard tracked, monitored, controlled and expelled them in accordance with law.

· Oct 16-20: A PLA Navy training ship task group visited Sattahip Naval Base, Thailand, as part of a far-seas deployment. Scheduled ports included Hong Kong (Sep 30-Oct 3), Cambodia (Oct 11-14), Thailand (Oct 16-20), and the next stop Singapore.

· Oct 17: China conducted a military exercise in waters near Scarborough Shoal.

· Oct 17: The USS Nimitz carrier strike group transited the Singapore Strait into the South China Sea to conduct operations.

· Oct 19: An Australian P-8A aircraft illegally intruded into airspace over China’s Xisha Islands without authorization; the PLA Southern Theater Command organized sea and air forces to track, monitor, deter and expel it. China said the action seriously infringed sovereignty and could easily trigger an accident.

· Oct 16-18: A China Coast Guard formation monitored Vietnam’s land reclamation activities on occupied features in the Spratlys, departing from Meiji Jiao (Mischief Reef) and patrolling within 2-5 nautical miles of seven features including Jinghong Dao, Qiong Jiao, Guihan Jiao, Bisheng Jiao, Liumen Jiao, Nanhua Jiao and Wumie Jiao. Vietnam’s expansion and reclamation on some Spratly features has continued for more than four years.

· Oct 23: New Zealand Navy replenishment ship HMNZS Aotearoa visited Ho Chi Minh City, Vietnam.

· Oct 26: The U.S. carrier USS Nimitz conducted flight operations in the South China Sea; within less than 30 minutes, an MH-60R Seahawk helicopter and an F/A-18 Super Hornet fighter jet crashed.

· Oct 27: Vietnamese and New Zealand naval vessels conducted a joint maritime drill in southern Vietnamese waters.

· Oct 30: HMAS Ballarat conducted a transit through the South China Sea supported by a U.S. Navy P-8A maritime patrol aircraft.

· Oct 30: UK Royal Fleet Auxiliary tanker RFA Tidespring (A136) conducted a freedom of navigation transit through the Spratly waters in the South China Sea.

· Oct 30: The United States and Brunei held their 31st Cooperation Afloat Readiness and Training (CARAT) exercise in Bandar Seri Begawan.

· Oct 30-31: The Philippines, the United States, Australia and New Zealand conducted the 12th Multilateral Maritime Cooperative Activity in the South China Sea.

· Oct 31: HMNZS Aotearoa visited Manila, Philippines.

· Oct 31: Canada was set to sign a Status of Visiting Forces Agreement with the Philippines, becoming the fourth country to establish such an arrangement with the Philippines.

· Oct 31: The United States announced that the Philippines and the United States launched a bilateral cooperation program called the “Philippines Task Force.”

· Oct 30-31: The Philippines organized so-called joint patrols with extra-regional countries, which China said seriously undermined regional peace and stability; the PLA Southern Theater Command dispatched forces to monitor the activities throughout to ensure they remained under control.

· Throughout October: The PLA Southern Theater Command sustained combat readiness patrols around Scarborough Shoal to strengthen control, respond to infringements and provocations, defend sovereignty and maintain regional peace and stability.

· Oct 31: The China Coast Guard conducted law-enforcement patrols around Scarborough Shoal; since October it has intensified tracking, warnings and expulsion of unlawful intruding vessels and aircraft to strengthen maritime control and safeguard sovereignty and rights.

November

· Nov 2: Canada and the Philippines signed a Status of Visiting Forces Agreement (SOVFA).

· Nov 14: With authorization, the Philippines delivered supplies to the warship illegally grounded at Second Thomas Shoal.

· Nov 14: The PLA Southern Theater Command organized a routine bomber patrol in the South China Sea, conducted amid so-called joint patrols by the Philippines with “external forces.”

· Nov 16: The Philippines, the United States and Japan conducted the 13th multilateral Maritime Cooperative Activity (joint maritime exercise) in the South China Sea, the eighth such activity this year.

· Nov 18: The United States, the Philippines, Malaysia, Thailand, Vietnam and Indonesia held the 2025 Southeast Asia Maritime Law Enforcement Initiative Commanders Forum to discuss shared maritime security challenges.

· Nov 18-20: The two militaries held the second 2025 China-U.S. MMCA working group meeting and the annual meeting.

· Nov 19-20: The Chinese and Vietnamese navies conducted their 39th joint patrol in the Beibu Gulf and carried out joint drills including search and rescue, communications, formation maneuvering and ship survivability maintenance.

· Nov 21: Chinese naval vessels and fighter aircraft warned and expelled a Philippine aircraft near Scarborough Shoal.

· Nov 24: China and Malaysia held the second bilateral dialogue on managing maritime issues in the South China Sea.

· Nov 24-26: China and ASEAN countries held the 50th Joint Working Group Meeting on the implementation of the DOC.

· Nov 26: JMSDF destroyer Harusame visited Subic, Philippines.

· Nov 26: The Philippines and India conducted their second bilateral Maritime Cooperative Activity in the South China Sea involving naval vessels and air force aircraft.

· Nov 28: The Philippines and France conducted a bilateral Maritime Cooperative Activity in waters off eastern Mindanao.

· Nov 28: China’s Ministry of Ecology and Environment released the Investigation and Assessment Report on the Ecological Environment of the Waters around Scarborough Shoal (2025), stating that environmental quality remained excellent and that the coral reef ecosystem was healthy and stable, while noting increasing thermal stress and non-negligible bleaching risks under intensifying climate change.

· Nov 29: The Philippines and Japan conducted a third bilateral Maritime Cooperative Activity in the South China Sea involving ships and aircraft.

· Nov 29: The PLA carried out combat readiness patrols in the waters and airspace around Scarborough Shoal. China said naval and air forces had been deployed since November to strengthen patrols and enhance management and control of surrounding waters.

· Nov 29: The China Coast Guard conducted law-enforcement patrols around Scarborough Shoal; since November it has intensified tracking, warnings and expulsion of unlawful intruding vessels and aircraft to strengthen maritime control and safeguard sovereignty and rights.

December

· Dec 2: The Philippines commissioned its newest frigate BRP Diego Silang (FFG-07). The Philippine Navy now has four missile frigates, including BRP Miguel Malvar (FFG-06), BRP Jose Rizal (FF-150) and BRP Antonio Luna (FF-151).

· Dec 4: The United States and Malaysia held the 31st exercise of Maritime Cooperation Readiness and Training in Lumut, Malaysia.

· Dec 9: The U.S. Navy said it had recovered two aircraft that crashed from USS Nimitz in the South China Sea the previous week.

· Dec 9-10: The Philippines and the United States conducted the 9th Maritime Cooperative Activity (joint drill) in the South China Sea.

· Dec 11: Chinese military and coast guard vessels reportedly expelled Philippine government and coast guard vessels from the area around Scarborough Shoal in recent days.

· Dec 12: Multiple small Philippine aircraft illegally entered the airspace over Scarborough Shoal; Chinese sea-air forces tracked, issued strong warnings and expelled them.

· Dec 12: A large number of Philippine vessels provoked trouble in waters around Sabina Shoal and rushed into the lagoon. Philippine fishing boats lingered inside the lagoon and repeatedly made malicious turns and other dangerous maneuvers; Philippine personnel even threatened Chinese law-enforcement officers on scene with knives. The China Coast Guard took necessary control measures in accordance with law, including warnings and maneuvering pressure to expel the vessels.

· Dec 15: The Philippines and the United States conducted the 10th bilateral Maritime Cooperative Activity in the South China Sea.

· Dec 16: The Philippines ordered expanded deployment of Philippine Coast Guard vessels in key areas of the South China Sea.

· Dec 25: A PLA Navy destroyer provided humanitarian assistance to a distressed Philippine fishing boat in the South China Sea, delivering food and drinking water to a fisherman.

· Dec 23: The Philippine military delivered Christmas care packages to the warship illegally grounded at Second Thomas Shoal and to eight other occupied Spratly features.

· Dec 29: China’s Ministry of Natural Resources and other agencies released the Scarborough Shoal Coral Reef Ecological Survey Report, stating that the overall condition of the Scarborough Shoal coral reef ecosystem is good.

· Dec 31: China Coast Guard conducted law enforcement patrols in Huangyan Dao territorial sea and its surrounding waters. Since December, the China Coast Guard and the PLA Southern Theater Command have maintained regular law enforcement and heightened maritime and aerial readiness patrols in and around Huangyan Dao.