Satellite imagery analysis shows that China’s maritime militia deployed to the South China Sea in record numbers in 2024. But in contrast to recent years, a majority of ships spent most of their days anchored at China’s military outposts rather than at unoccupied reefs where they might pretend to fish. This suggests Chinese authorities are not pressuring vessel owners to maintain the crumbling façade of the militia as a legitimate fishing fleet, and as a result the vessels are prioritizing the easier resupply, safety, and comfort available when they are within the lagoons of China’s island bases.
Methodology
China’s maritime militia is the largest fleet of ships operating in the disputed waters of the South China Sea. But unlike the China Coast Guard, most militia cannot be observed on satellite-based automatic identification system platforms. To track the militia’s presence across disputed waters, AMTI examined Planet Labs satellite imagery for the calendar year 2024 at 11 features in the South China Sea that militia ships are known to frequent. Militia vessels were counted in imagery an average of four times per month at each feature, and data on days between observations was interpolated linearly between the two nearest observations to enable comparison across features.
Most of these vessels are members of China’s Spratly Backbone Fishing Fleet, the civilian component of the militia which is numerically larger than the professional component AMTI profiled in December. Although by regulation, these vessels can be as small as 35 meters in length, only ships falling between 45 and 65 meters were counted for the purposes of this study. This is the most common length for Chinese militia trawlers and a range rarely seen in other vessels active in disputed waters, such as China Coast Guard or fishing vessels of other coastal states.
By the Numbers
The data reveals that China’s militia was out in greater number in 2024 than in previous years. The average number of militia ships across all 11 observed features in 2024 rose to 232, a 15 percent increase from 2023’s average of 195. As usual, most militia ships deployed to the Spratlys at the end of the Lunar New Year and stayed in the area until the end of the calendar year—meeting the 280-day minimum requirement to receive government payments as part of the Spratly Backbone Fishing Fleet.
The most dramatic shift during the year occurred at Mischief Reef, where the number of vessels surged to 173 on July 24 and reached a peak of 200 in late October. Nearly half of these vessels likely came from Union Banks, where the data shows a shift of vessels first from Whitsun Reef to nearby Hughes Reef in June, and then a sharp drop at Hughes in July, which coincides with the increase at Mischief. But this movement can account for only 80 vessels, meaning the majority of ships at Mischief in July had to have come from locations other than the observed features—most likely directly from homeports in Hainan and Guangdong provinces.
A similar spike occurred last summer at Mischief but quickly receded. This time the ship counts remained elevated through the end of the year. Tensions at nearby Second Thomas Shoal cannot fully explain this surge, which didn’t occur until Manila and Beijing had reached an agreement to reduce tensions at the shoal. But it is possible that ships lingered longer at Mischief in case that agreement fell apart and tensions flared again.
Given the increase in China-Philippines tensions around Sabina Shoal in 2024, the feature was added as an area of observation in this year’s study. It averaged just nine militia ships per day, with a marked drop in ship numbers in June and a surge in August, coinciding with collisions between Philippine and Chinese ships at the shoal.
Average militia presence fell by nearly half around the smaller Chinese bases at Hughes and Gaven reefs compared to 2023, while unoccupied Whitsun Reef, which was the site of huge deployments beginning in 2021, saw a more mild decrease. Meanwhile, Iroquois Reef, Scarborough Shoal, Second Thomas Shoal, Subi Reef, and Thitu Island all saw minor increases in 2024.
Show’s Over
It is no surprise that China’s militia presence has increased year over year, but their concentration within the ports of China’s large Spratly outposts is a shift. Just two years ago, the majority of militia ships spent their days at Union Banks and other unoccupied features while outposts like Mischief Reef hosted fewer than 15 ships on average. The high presence at Mischief in 2024 is probably tied in part to events at nearby Second Thomas and Sabina shoals. But it also appears to reflect a waning interest in keeping up the masquerade that these are commercial fishers. With the militia’s activities and identities now widely known, Beijing may be opting to drop the act and simply deploy its paramilitary forces where they are most useful or easiest to sustain.
