The presence of China Coast Guard (CCG) vessels at Bajo de Masinloc (Scarborough Shoal) surged sharply during the first half of 2026, nearly matching the total patrol activity recorded in 2025, according to a new report by the Asia Maritime Transparency Initiative (AMTI). Using automatic identification system (AIS) data collected from Jan. 1 to June 30, AMTI found that CCG vessels accumulated 933 ship-days around Bajo de Masinloc during the six-month period, close to the 1,099 ship-days logged throughout 2025. The report highlighted that monthly CCG patrols averaged 156 ship-days in the first half of 2026, up from 90 ship-days during the same period last year.

Patrol activity peaked in May with 216 ship-days. Chinese coast guard vessels expanded their patrol coverage around the shoal, with multiple ships coordinating to maintain a perimeter extending roughly 30 nautical miles from Bajo de Masinloc. Within that area, six to eight Chinese maritime militia vessels maintained a near-continuous presence closer to the shoal.

Some Chinese coast guard ships also continued patrolling along — and at times beyond — China's self-declared nine-dash line to intercept Philippine vessels heading toward the disputed feature. Philippine maritime patrols also increased during the period but remained significantly lower than China's. The Philippine Coast Guard and the Bureau of Fisheries and Aquatic Resources recorded an average of 43 ship-days per month during the first half of 2026, a 43-percent increase from the 30 ship-days per month logged during the same period in 2025.