China contests maritime boundary negotiations between Japan and the Philippines

Tensions are rising in the South China Sea and East China Sea following maritime developments involving China, Japan, the Philippines, and Taiwan. During a May 2026 summit, Japan and the Philippines agreed to elevate their bilateral relations to a Comprehensive Strategic Partnership and commenced formal negotiations to delimit their exclusive economic zone (EEZ) and continental shelf boundaries east of Taiwan.

China responded to these maritime boundary intentions with a special maritime law enforcement operation intended to discourage negotiations without Chinese participation. Critics argue this operation is inconsistent with international law, as it impedes high seas freedoms of navigation and violates the principle of exclusive flag State jurisdiction.

Simultaneously, the Philippines submitted an official nautical chart of Scarborough Shoal to the United Nations to bolster its claims in the area. While China protested the filing as an infringement on its sovereignty, Taiwan has adopted a cautious approach. Taipei is balancing its own historical claims to the shoal with the need to maintain a security partnership with Manila against Chinese pressure. Experts note that while Taiwan’s exclusion from the UN limits its procedural ability to advocate for its claims, it does not invalidate its substantive sovereignty assertions.