Key facts
- The Philippines will file an updated maritime chart with the UN to reinforce its South China Sea claims.
- The updated map aims to help Manila identify and challenge competing claims in precise legal terms.
- Chinese force movements in the South China Sea increased by approximately 490% in the first half of 2026.
- These Chinese activities are concentrated within the Philippines' Exclusive Economic Zone, around Thitu Island and other features.
- China claims almost the entirety of the South China Sea based on historical rights within the 'nine-dash line'.
- An arbitration court at The Hague ruled a decade ago that China's nine-dash line has no basis under international maritime law.
The Philippines is preparing to submit an updated maritime chart to the United Nations as part of its efforts to bolster its claims in the disputed South China Sea. While the document will not establish sovereignty, it is intended to provide a more precise legal basis for Manila to identify and challenge competing territorial assertions.
This initiative occurs against a backdrop of escalating tensions and the normalization of "gray zone" tactics in the region. Data from ACLED indicates a significant increase in Chinese maritime activity, including survey vessels, China Coast Guard deployments, and maritime militia, particularly within the Philippines' Exclusive Economic Zone (EEZ). These activities often result in confrontations such as harassment and blocking maneuvers, aimed at altering the status quo and consolidating control without resorting to open military conflict.
China asserts historical rights over nearly the entire South China Sea, demarcated by its "nine-dash line." However, this claim was significantly undermined a decade ago when an arbitration court in The Hague ruled it had no basis under international maritime law, affirming the Philippines' EEZ. Despite being a signatory to the UN Convention on the Law of the Sea (UNCLOS), China rejected the ruling. The Philippines, meanwhile, refers to its EEZ as the West Philippine Sea.
Former Chinese diplomat Victor Gao has suggested that islands like Thitu, located in the Spratly Islands, are likely to be taken over by China, dismissing the safety of Filipinos in certain areas as a "fantasy." In response, Philippines Defense Secretary Gilberto Teodoro has characterized China's actions as irresponsible and provocative, emphasizing that appeasement is not an effective strategy.