The China Coast Guard (CCG) remains the dominant state actor in disputed waters of the South China Sea. Analysis of AIS data from commercial providers MarineTraffic and Starboard Maritime Analytics show that the CCG continued to maintain daily patrols at key features across the South China Sea in 2023.  Taken together with the CCG’s leadership during confrontations with other claimants like the Philippines, these patrols demonstrate the centrality of the CCG in China’s peacetime operations to assert control over its vast claims in the South China Sea.

China Coast Guard Patrols in the South China Sea

AMTI examined historical AIS data from the year 2023 across five features most frequented by Chinese patrols: Second Thomas Shoal, Luconia Shoals, Scarborough Shoal, Vanguard Bank, and Thitu Island. Comparison with 2022’s data shows that the CCG maintained a similar degree of presence, with a slight shift in attention away from Vanguard Bank and toward Luconia Shoals and Second Thomas Shoal.

Calendar days patrolled at Second Thomas Shoal, the site of frequent Philippine-China tensions in 2023, increased to 302 from 279 in 2022. The number of days patrolled at Luconia Shoals, near a major cluster of Malaysian oil and gas operations, also increased from 316 to 338.  Scarborough Shoal and Thitu Island saw minor decreases in 2023, from 344 to 311 and 208 to 206 days, respectively. And at Vanguard Bank, the days patrolled fell significantly in the data, from 310 days in 2022 to 221 days in 2023. In total, patrols observed in 2023 at these five features amounted to 1,652 ship-days.

But the nature of AIS data means that these numbers are only a baseline, and that the true number of days patrolled by the CCG is likely higher. CCG vessels are not always observable on commercial AIS platforms, either because their transceivers are disabled or not detectable by satellite AIS receivers. For example, satellite imagery of Thitu Island from March 20, 2023, revealed a Zhaojun-class (Type 718B) CCG cutter was on station, despite AIS platforms showing no corresponding signal.

A Zhaojun-class China Coast Guard cutter at Thitu Island, March 20, 2023

CCG behavior while on patrol was similar to years past, with vessels stationed at Luconia Shoals and Vanguard Bank often making day trips to pass through nearby Malaysian and Vietnamese oil and gas operations. A new trend occurred at Second Thomas Shoal, where CCG on patrol also made excursions to nearby Sabina Shoal, where the Philippines has accused Chinese vessels of causing damage to coral reef within the lagoon.

The CCG has already made headlines several times in 2024 for using water cannons against Philippine supply ships at Second Thomas Shoal. But the CCG’s continuous patrols at all corners of the nine-dash line mean that it’s only a matter of time before a close encounter occurs with Vietnam or Malaysia.