Japan-Philippines Maritime Border Delimitation: A Step Toward Narrowing the PRC’s Window for Launching an Invasion of Taiwan

On May 28, 2026, Prime Minister of Japan Sanae Takaichi and Philippine President Ferdinand Marcos Jr. decided to begin negotiations on the delimitation of maritime boundaries and the continental shelf.

The area in question is the western Philippine Sea, stretching from Japan’s Okinawa Prefecture to the Philippine province of Batanes and, in effect, running along the entire eastern edge of the island of Taiwan.

Until now, such a dialogue had been impossible because of the preserved status quo around Taiwan’s economic zone and the risk of escalation by China.