In mid-August, after China’s annual unilateral fishing ban ended, more than 6,000 Chinese fishing boats went to sea on a large scale and dispersed across the vast sea.
This scene is reminiscent of the Battle of Chibi, when Cao Cao led thousands of warships to line up on the river to confront the coalition forces of Sun Quan and Liu Bei.
The difference is that these fishing boats did not sail to a naval battle, but dispersed to different fishing grounds, including Vietnam's exclusive economic zone and the waters off Quang Ngai Province, a central and southern coastal province. Maritime researchers say the number of Chinese fishing boats in the waters has increased significantly in recent years.
What once seemed like a seasonal fishing operation now reflects a larger issue: competition for marine resources, fishermen's livelihoods and broader strategic calculations surrounding control of the South China Sea.
Researchers from the SeaLight project of the Gordian Knot Center for National Security Innovation at Stanford University found that a large number of Chinese fishing boats gathered near the coast of Vietnam.
Citing maritime data, they said the fleet has about 100 ships, most of which depart from Guangxi ports and have been operating off the coast of Quang Ngai Province in Vietnam since 2024. The closest distance to Ly Son Island is only 28 nautical miles, or nearly 52 kilometers.
Ray Powell, director of the SeaLight project, told BBC Vietnam: "We checked the data from 2024 to 2026 and found that there were more than 40 ships per day in 2026, which is much more than what we have seen in previous data, and the numbers are still rising."
"Things haven't really stabilized, so it looks like this problem is only going to continue."
seasonal patterns
Data provided by SeaLight shows that Chinese fishing boats appear very close to the coast of Vietnam at certain times of the year.
Grace Gabrielli, a SeaLight intern who was directly involved in analyzing maritime data, said: "Judging from their activity patterns, they travel to and from different ports, stop in Quang Ngai Province, and then return to the port. This is a common activity pattern for fishing vessels."
The data shows that this fleet was particularly active in late 2025 and the first few months of 2026, with the exception of February 2026.
Carl Thayer, a professor at the University of New South Wales in Australia, said that this pattern can be explained to a certain extent by China’s annual unilateral fishing ban. The fishing ban lasts from May 1 to August 16 at noon.
He explained: "There is the Lunar New Year at the beginning of the year, and you will see some ships that were originally there return to China to celebrate the New Year. Then they come back, and they gather in large numbers from March to May. By the end of April, they start to withdraw, including some escort ships. After the fishing season restarts in mid-August, they come back."
The fleet includes government and military ships
Powell, a former US Air Force attaché in Vietnam, told the BBC that the activities of most Chinese ships in this area are similar to ordinary fishing boats and are indeed engaged in fishing. However, the fleet also includes government ships and maritime militia vessels.
Notably, SeaLight spotted a Chinese government vessel operating alongside the fishing fleet during the same seasonal event, which SeaLight identified as a military vessel.
"The government ship we found was classified as a military vessel, flew the Chinese flag, had zero fishing activity recorded, and the timing of its appearance was consistent with the seasonal patterns of the fleet. In other words, it seemed to be moving back and forth with the entire fleet," Powell said.
He said this showed that government vessels were accompanying fishing fleets, a pattern that was "very consistent with the activity of militia vessels at sea."
"When a vessel that is clearly classified as a government vessel is mixed in, what we are seeing is Chinese government-sanctioned fishing off the coast of Vietnam," he said.
Powell believes that China "cannot claim, and indeed does not want to claim, that this is just a group of fishing boats doing their own thing."
He explained: "China wants Vietnam to know that it is monitoring and recognizing these activities; if Vietnam poses a significant challenge to these fishing activities, China is ready to protect them."
He added: "China is also sending a geopolitical message to Vietnam that it can operate anywhere within the scope of its claims, and Vietnam has very limited means to stop it."
Thayer also believes that the activities of this fleet are likely to be supported by the Chinese government.
"China is not going to just send some unarmed fishing boats to the South China Sea to fish and make money and then go home," he said. "They need to protect these boats because they will say, this is our place and we have to intimidate everyone else and drive them out."
However, Thayer warned that no assumptions should be made about the identity of the fishermen themselves.
He said: "We have no definite photographic evidence. Some analysts call them 'little blue men', which means that one moment they are still fishing, the next moment they enter the cabin, and when they come out they have put on blue uniforms and become maritime militia."
Therefore, he believes that the fleet may be composed of a variety of personnel and vessels, including commercial fishermen, government-subsidized militia, and larger maritime law enforcement vessels, some of which are militia-type, as well as Chinese Coast Guard vessels.
Why Quang Ngai Province?
Quang Ngai Province is located in central Vietnam, with rich fishing grounds and abundant marine resources.
Its vast sea area and favorable natural conditions support a variety of fish and seafood, including tuna, mackerel, jack mackerel, anchovies, squid and shrimp.
Fishing has long been an important part of life in coastal communities, especially on islands and coastal areas. Each voyage not only brought back a large amount of food, but also provided employment opportunities and brought income to the local economy.
According to Vietnam News Agency, as of May 2026, there are close to 5,000 registered fishing boats in the fishing boat management system of Quang Ngai Province. Local fishermen have also been operating in the fishing grounds around the Paracel Islands and Nansha Islands for a long time and have rich experience.
However, in the waters surrounding the Xisha and Nansha Islands, Vietnamese fishing boats are often driven away and attacked by China, fishermen are beaten, and their property has been seized or confiscated.
On September 29, 2024, the fishing boat QNg 95739 TS in Quang Ngai Province was attacked by Chinese personnel. Fishermen on board said they were beaten and had their nets, equipment and "tons of fish" taken away. At least 10 Vietnamese fishermen were injured.
Reuters reported on October 1, 2024 that the Chinese Ministry of Foreign Affairs stated that Vietnamese fishing boats "illegally entered the waters of China's Paracel Islands for fishing without the approval of the Chinese government, and relevant Chinese departments took measures to stop them in accordance with the law." However, Beijing did not directly mention the September 29 attack.
On October 2, 2024, the Vietnam Fisheries Association issued an official document to the Ministry of Agriculture and Rural Development, the Ministry of Foreign Affairs, and the Central Committee of the Communist Party of Vietnam, "Protesting against China's obstruction of operations, plundering property, and attacks on fishermen, and recommending strengthening support for fishermen operating at sea."
Earlier, in April 2020, Vietnamese media reported that a fishing boat in Quang Ngai Province was hit and sunk by a "foreign vessel" near Woody Island. China later returned the eight fishermen on board.
Powell said that the simplest explanation for Chinese fishing boats operating in this area is that there are abundant fish here. However, he emphasized that these activities also serve Beijing's strategic and geopolitical goals.
"The presence of these fishing boats there several months a year, and certainly without asking Vietnam's permission, is an end in itself, not an accident," he said. "Because it helps China assert its claim to rights in these waters, even though under international law that is not the case."
SeaLight intern Gabrieli added: "The local enforcement of the exclusive economic zone is limited, and the fishing grounds are very rich. I think China has discovered in recent years that the resources here are rich but the enforcement is limited, so it is taking full advantage of this situation."
What does it mean for Vietnamese fishermen?
Professor Thayer, who has twice traveled to Quang Ngai Province to study the lives of local fishermen, said that fishermen often go out to sea at night and go to the waters near the Paracel Islands. They are "willing to take risks" because the most valuable and profitable seafood can be caught there.
He pointed out that according to SeaLight data, China used a large number of maritime militia and maritime law enforcement vessels to form a large "barrier" in 2024 and 2025 to prevent Vietnamese fishermen from entering relevant waters.
As a result, he said, fishermen from Quang Ngai Province have told him that they are forced to move to other places to operate, such as the Gulf of Tonkin (Gulf of Tonkin) or the waters around Indonesia's Natuna Islands.
"They do complain to the media, including foreign media, and even if they ask for help, they can't get immediate assistance. They are left alone. When they go out to sea, there are insufficient local patrols, and sometimes no patrols at all," he said.
As a result, Thayer believes these fishermen are vulnerable.
He recalled: "China has steel-hulled militia ships, and coast guard ships have also used water cannons. So fishermen said that when they see ships approaching, because the Chinese ships are much faster, they will try to escape, but sometimes they still get caught up due to distance and other reasons."
As a result, he said, the fishing grounds for Vietnamese fishermen in this area have become increasingly restricted.
For the coastal communities in Quang Ngai Province, this is not just a story about fishing grounds, but also about the livelihoods of generations of families who rely on the sea.
In January 2024, the Chairman of the Vietnam Fisheries Association and the Chairman of the Da Nang Fisheries Association told BBC Vietnamese that at that time, in order to avoid being threatened by Chinese maritime militia and law enforcement vessels, fishermen had to maintain a distance of dozens of nautical miles from the fishing grounds of the Paracel Islands.
Chen Wenling, chairman of the Da Nang Fisheries Association, also described the presence of a large number of Chinese maritime militia vessels based on reports from local fishermen.
Chen Wenling said: "They appear in rounds of actions. As soon as the fishing ban ends, they flood into Vietnamese waters in large numbers. Our fishermen will be scared when they see them, because there are so many, there can be hundreds or even thousands of boats, sweeping across our fishing grounds very powerfully."
Vietnam and China’s response
Regarding reports on the activities of Chinese fishing boats off the coast of Quang Ngai Province, the BBC has sent an email to the Vietnamese Ministry of Foreign Affairs seeking an official response, but did not receive an immediate reply.
The BBC also contacted the Vietnam Fisheries Association for a response and more information, but received no reply.
China has implemented a three-and-a-half-month unilateral fishing ban every year since 1999, and Vietnam has opposed it for many years.
On May 5 this year, Vietnamese Foreign Ministry spokesperson Pham Thu Heng stated at a regular press conference: "Vietnam's position on China's fishing ban in the South China Sea is consistent and has been clearly reiterated over the years."
Pham Thu Heng also stated that Vietnam has asked China to respect the rights of Vietnamese fishermen to legally operate in Vietnamese waters and waters beyond national jurisdiction in accordance with international law, especially the 1982 United Nations Convention on the Law of the Sea.
Thayer said that although the Vietnamese government and the Vietnam Fisheries Association have protested, these actions have mainly remained at the verbal level, and Vietnam has not deployed significant forces in the relevant waters.
He said: "In a sense, these protests have no effect. The problem is that if actual action is taken, it will be in vain to a certain extent, because China has an overwhelming advantage in terms of the number of ships and the tonnage of ships. Vietnam will not gain anything from this, it will only be pushed back."
However, he pointed out that Vietnam will definitely raise these issues when the top leaders of the two countries meet. He said both sides generally agreed that bilateral relations should continue to develop and that tensions in the South China Sea should not overshadow the broader relationship between the two countries.
Powell had a similar view. He said that China-Vietnam relations have always been managed very carefully, so that it is not easy for both sides to publicly make very negative remarks about each other.
Powell said the two countries were trying to maintain a stable relationship despite what he described as "very, very sharp" differences, particularly over the South China Sea, the Paracel Islands and waters closer to Vietnam's coast.
The most recent controversy occurred in early September 2026. Less than a week after Vietnam "firmly opposes" all foreign activities in the Paracel Islands in the South China Sea, China's Foreign Ministry said Vietnam had no right to comment.
Chinese Foreign Ministry spokesperson Guo Jiakun told reporters on September 3: "The Paracel Islands are China's inherent territory and there is no dispute. China's necessary construction on its own territory is a matter within the scope of sovereignty, and Vietnam has no right to make irresponsible remarks."
Hanoi's statement and Beijing's tough response coincided with reports in mid-August that China was carrying out new construction activities on Yagong Island. Yagong Island is located about 14 kilometers northeast of Antelope Reef.
Security experts said it is still too early to determine the purpose of the facility, but it may be an early warning radar facility to support facilities China plans to build on Antelope Reef. Antelope Reef is gradually becoming one of the largest artificial islands in the Nansha and Paracel Islands.
Vietnam has also accelerated its reclamation and island building in the Nansha Islands in recent years. Observers said: "China will definitely not be happy about this."
Powell said China was not harassing Vietnamese dredgers or taking similar actions. In other words, Beijing chose not to respond directly but to demonstrate its power in other ways, one of which was fishing off the coast of Quang Ngai Province.
"It can be a way to remind Vietnam who is the most powerful here without having to announce it to the world," he said.
Strategic considerations involving Taiwan
Beijing appears to be particularly focused on the Philippines, in part because it is a U.S. ally and China is keen to reduce U.S. influence in East Asia.
The Philippines has also adopted a so-called "transparency initiative" that involves filming contacts between the two sides at sea and releasing relevant images and videos in the hope of publicly exposing China's actions.
In contrast, Vietnam is usually more cautious and does not allow the disclosure of images of maritime confrontations and accidents involving China, including cases of fishermen being attacked at sea.
Unless official spokespersons from the Ministry of Foreign Affairs or Fisheries Associations respond publicly, or foreign journalists are able to travel to the local area to talk directly to the fishermen, information on related incidents is difficult to find in the media.
Observers therefore say that much of the public is unaware of what is happening within Vietnam's exclusive economic zone.
Powell said Vietnam's approach allows Hanoi to avoid direct confrontation with Beijing and keep tensions at a low level, rather than escalating like between China and the Philippines.
But he also said that the disadvantage of this approach is that China has adopted a gradual, systematic and sustained strategy. Over the years, China’s activities involving Vietnam’s claims and sovereign rights have increased.
He gave an example: "In 2023, we tracked a survey activity off the southern coast of Vietnam. They basically spent a month making the survey ship sail in the shape of the Chinese character '中'."
"They have allowed survey ships, Chinese coast guard and maritime militia to sail in this trajectory for a whole month. This is a pretty amazing thing. China is very high-profile and bold in doing this."
Powell said that this incident is a reminder to Vietnam that China has never reduced its claims. "This is a reminder to Vietnam that China's claims will never go backwards. They will never claim less, they will only make more and more claims."
Chinese fishing boats have been operating within Vietnam’s exclusive economic zone for many years. However, Powell said that related activities have continued to increase over the past four years or so, and reached particularly high levels in May this year, which is a trend that is particularly noteworthy.
"In the long run, it's only likely that more and more of this activity will gradually expand southward," he concluded.
