Tensions Escalate in West Philippine Sea Amid Joint Naval Exercises and Chinese Vessel Incursions

By Cliff Potts, Foreign Affairs Corresponden

August 6, 2025

MANILA, Philippines — The West Philippine Sea, a critical maritime region within the Philippines’ exclusive economic zone (EEZ), saw heightened activity from July 30 to August 5, 2025, as the Philippine Coast Guard (PCG) and Navy responded to Chinese vessel movements while conducting historic joint exercises with the Indian Navy. The developments underscore ongoing territorial disputes with China, which continues to assert claims over the South China Sea despite a 2016 arbitral ruling favoring the Philippines.

On August 2, the PCG deployed an aircraft to monitor the Chinese research vessel Xiang Yang Hong 05, spotted approximately 37 nautical miles off Sta. Ana, Cagayan, in the Luzon Strait near Batanes. Despite repeated radio challenges, the vessel continued its “marine research” within the Philippine EEZ, raising concerns about unauthorized activities. The PCG’s maritime domain awareness flight aimed to assert Philippine sovereignty in the area (@newswatchplusph, 2025).

Meanwhile, the Philippine Navy made history with its first-ever joint sail with the Indian Navy on August 3-4. The exercise involved the Indian Navy’s oil tanker INS Shakti (A57) and the Philippine Navy’s BRP Miguel Malvar (FFG-06) and BRP Jose Rizal (FF150), conducting a replenishment-at-sea maneuver in the West Philippine Sea. The operation strengthened bilateral defense ties, signaling a united front against regional tensions (@ABSCBNNews, 2025). However, the exercise was overshadowed by the presence of two Chinese warships—a Jiangkai-class frigate and a Luyang-class vessel—spotted near the Philippine EEZ, heightening vigilance among Filipino forces (@News5PH, 2025).

The PCG also faced scrutiny over a video released by the China Coast Guard (CCG), claiming it successfully towed Philippine Navy boats away from Ayungin Shoal and the BRP Sierra Madre. PCG Spokesperson Jay Tarriela dismissed the claim, clarifying that no such incident occurred and reaffirming the Philippines’ commitment to maintaining its presence at the shoal (@gmanews, 2025). The BRP Sierra Madre, grounded at Ayungin since 1999, remains a flashpoint in the dispute, symbolizing Manila’s resolve to defend its maritime rights.

These events follow a broader pattern of Chinese assertiveness, including the presence of 37 Chinese vessels near Pag-asa Island and 12 at Escoda Shoal from July 30 to August 5, as reported by the Philippine Navy (Philippine Star, 2024). The Navy also monitored a Chinese survey ship, San Hao, in the region, prompting increased patrols to ensure no artificial structures, such as piled corals, were being created (Philippine Star, 2024).

Philippine officials, including President Ferdinand Marcos Jr., continue to advocate for diplomacy while bolstering defense capabilities. The commissioning of the BRP Miguel Malvar, the nation’s first guided-missile frigate, on the Navy’s 127th anniversary in May 2025, reflects Manila’s push to modernize its forces amid growing threats (Indo-Pacific Defense Forum, 2025). Marcos has also expressed openness to dialogue with former President Rodrigo Duterte regarding a rumored “secret deal” with China, highlighting the complexity of navigating domestic and international pressures (Manila Bulletin, 2025).

As tensions simmer, local advocates are pushing for greater public awareness. A new bill, the West Philippine Sea Mandatory Education Act of 2025, filed on July 9, aims to make lessons on the 2016 arbitral ruling and Philippine maritime rights mandatory in schools (Philippine Star, 2025). The Atin Ito coalition has similarly urged integrating West Philippine Sea issues into the national curriculum, emphasizing the cultural and economic significance of the region (Manila Bulletin, 2025).

The Philippines’ actions—balancing military modernization, international partnerships, and diplomatic restraint—reflect a calculated response to China’s provocations. Yet, with Chinese vessels maintaining a near-constant presence, the West Philippine Sea remains a volatile theater where sovereignty and stability hang in the balance.

References
ABSCBNNews. (2025, August 4). Indian Navy, Philippine Navy conduct replenishment-at-sea exercise in West Philippine Sea. X Post.
GMA News. (2025, August 1). PCG Spokesperson Jay Tarriela on China Coast Guard video claims. X Post.
Indo-Pacific Defense Forum. (2025). Philippine Navy commissions first guided-missile frigate, showcases US-provided USVs. IP Defense Forum. https://ipdefenseforum.com
Manila Bulletin. (2025). Balita: West Philippine Sea issues in curriculum, Romualdez on maritime tensions. Manila Bulletin. https://balita.mb.com.ph
News5PH. (2025, August 4). Chinese warships spotted during PH-India joint sail. X Post.
Newswatchplusph. (2025, August 3). PCG deploys aircraft to monitor Chinese research vessel. X Post.
Philippine Star. (2024, August 6). China steps up presence in critical areas of West Philippine Sea. Philstar.com. https://www.philstar.com
Philippine Star. (2025, July 9). New bill requires lessons on 2016 ruling, China’s presence in the West Philippine Sea. Philstar.com. https://www.philstar.com