Over the past year, the Asia Maritime Transparency Initiative and the Center for Advanced Defense Studies conducted a study of China’s maritime militia using remote sensing data and open-source Chinese language research. The resulting report, Pulling Back the Curtain on China’s Maritime Militia, features the most comprehensive study to-date of the structure, subsidies, and ownership networks of China’s maritime militia in the South China Sea, as well as a methodology for identifying Chinese maritime militia vessels and a list of over 120 militia vessels thus identified.

The full report can be accessed here:

Pulling Back the Curtain on China’s Maritime Militia (full PDF download)


Menyingkap Semula Tirai Tentera Maritim Cina (Malay Translation)

Vén màn s tht v Dân quân Hàng hi Trung Quc (Vietnamese Translation)

Executive Summary

Since completing the construction of its artificial island outposts in the Spratly Islands in 2016, China has shifted its focus toward asserting control over peacetime activity across the South China Sea. A key component of this shift has been the expansion of China’s maritime militia—a force of vessels ostensibly engaged in commercial fishing but which in fact operate alongside Chinese law enforcement and military to achieve Chinese political objectives in disputed waters.

The tactics employed by the militia pose a significant challenge to those interested in maintaining a maritime order rooted in international law. But open-source Chinese language research, remote sensing data, and maritime patrols conducted by actors operating in disputed waters have the power to expose the militia and diminish its effectiveness as a gray zone force.

This report presents the most comprehensive profile yet available of China’s maritime militia in the South China Sea. Additionally, this report presents a methodology for identifying Chinese maritime militia vessels and a list of 122 militia vessels thus identified, as well as a list of 52 more ships highly likely to be militia.

History of the Militia

  • China’s modern use of fishing militias dates back to at least 1974, when they were employed in seizing the Paracel Islands from the Republic of Vietnam. Several developments in the 1980s, including the 1985 establishment of a militia force in Tanmen Township on Hainan and the establishment of China’s first bases in the Spratlys in 1988, would lay the groundwork for a more active militia in the following decades.
  • The militia’s involvement in aggressive operations increased in the 2000s, when militia vessels physically interfered with the navigation of multiple U.S. Navy ships. This continued into the early 2010s, where the militia would play a key role in China’s seizure of Scarborough Shoal in 2012, as well as the deployment of a Chinese oil rig into Vietnamese waters in 2014.
  • Since the completion of China’s artificial island outposts in 2016, militia boats have been deployed to the Spratlys in greater numbers and on a more constant basis than ever before. Militia have accompanied Chinese law enforcement at several oil and gas standoffs with Malaysia and Vietnam and have participated in mass deployments at targeted features; nearly 100 militia boats deployed near Philippine-occupied Thitu Island in 2018, and approximately 200 gathered at unoccupied Whitsun Reef in the spring of 2021.

The Modern Militia

  • The militia as currently constituted in the South China Sea operates from a string of 10 ports in China’s Guangdong and Hainan Provinces. Remote sensing data indicates that roughly 300 militia vessels are operating in the Spratly Islands on any given day.
  • Militia ships fall into two major categories: professional militia vessels and commercial fishing boats recruited into militia activity by subsidy programs and known as Spratly Backbone Fishing Vessels (SBFV). Professional vessels are generally built to more rigorous specifications that include explicitly military features, although even SBFVs are steel-hulled and measure at least 35 meters, with many measuring 55 meters or more. Both professional militia and SBFVs participate in large deployments aimed at asserting Chinese sovereignty, and both deny access to ships from foreign countries, but statements from Chinese officials suggest that more aggressive operations would first be entrusted to professional militia vessels.
  • Militia activities violate several tenets of international law. Efforts to block the lawful activities of other claimant states within their exclusive economic zones are in violation of the United Nations Convention on the Law of the Sea and customary international law. Unsafe maneuvers intended to impede the operations of foreign ships by creating a risk of collision violate the International Maritime Organization’s Regulations for Preventing Collisions at Sea, or COLREGS.

Government Subsidies, Funding, and Support

  • A wide array of central and local government programs have been implemented in recent years to finance the militia. These include dual fuel subsidies for SBFVs operating in waters around the Spratly Islands, subsidies for the construction of fishing vessels (including SBFVs) targeting the Spratly waters, subsidies for construction of professional militia vessels, subsidies for the installation and renovation of equipment on board fishing vessels, construction loan interest subsidies, and training programs aimed at recruiting military veterans to work in the militia.
  • Full-time maritime militia personnel working in state-owned fishing enterprises engaged in maritime militia operations receive salaries from those enterprises.
  • Existing subsidy policies incentivize the operation of large vessels in disputed waters while providing no incentive to fish. Vessels at least 55 meters in length with an engine power of at least 1,200 kW operating in the Spratly Islands receive special fuel subsidies at a rate of CNY 24,175 (USD 3743.30) per day—a rate which well exceeds operational costs, allowing owners to easily profit by deploying to disputed waters without fishing at all.

On-Shore Owners

  • The ownership structures of militia and likely militia vessels are simple: an examination of registered owners indicates that 90 percent of vessels analyzed are either directly owned by, or one entity removed from, their ultimate beneficial owner. This suggests owners are unconcerned with hiding their connection to the militia.
  • Militia ownership appears to be concentrated in the localities from which they operate: of the 28 companies identified as directly owning militia vessels, 22 are based in Guangdong and 5 are based in Hainan.
  • Despite geographic concentration, direct ownership of militia and likely militia vessels is only moderately centralized. The 96 vessels analyzed had a total of 64 direct owners, making for a ratio of roughly 1.5:1.
  • Most militia and likely militia vessels’ ownership networks were not found to be linked to the Chinese government.
  • Professional militia vessels were underrepresented in ownership data, but they are likely both more centralized and more directly linked to government entities.

Identifying Militia Vessels

  • Direct identification in official Chinese sources or state media remains the most straightforward and conclusive indicator of militia activity. However, it is unlikely that most maritime militia vessels can be identified in this way. This makes behavior-based identification—informed by remote sensing data and traditional on-site reporting—the most promising avenue for continued identification.
  • On-site photography and video, as well as ship-to-ship automatic identification system (AIS) data collection, offer the greatest potential to directly identify militia vessels and document their behavior. This both enhances the opportunities for follow-up research and creates an immediate impact by revealing the militia’s size, scope, and activities to a broad audience in a convincing fashion.
  • Commercial satellite imagery and AIS data play an important role in identifying and tracking militia deployments. These tools may prove even more effective in the future, given what has been learned about the militia’s behavior and geographic distribution.
  • Association with known militia vessels and ports are strong indicators that a vessel warrants further study, as are large subsidies indicating that a ship is an SBFV. Large vessels over 50 meters operating in disputed waters—especially understaffed vessels with less than 10 crew members— are also deserving of further scrutiny.
  • By coupling continued reporting efforts from actors in the South China Sea with additional research using open-source Chinese-language materials and remote sensing data, the complete identification of the maritime militia is not only possible, but likely.


This report was made possible by funding from the Department of State’s Global Engagement Center. CSIS would like to thank the Institute of War and Peace Reporting for their assistance in administering this project.