The ships that do not want to be found
On May 14, 2026, a VLCC named the Success anchored in the waters off Kish Island, a Iranian free zone in the Persian Gulf. It loaded approximately 1.9 million barrels of Iranian Light crude. Then it sailed east, passing through the Strait of Hormuz on May 16, one of the few large tankers to transit the strait since the crisis began. Its AIS transponder showed a destination of Zhoushan, China. Then, on May 19, somewhere in the eastern Arabian Sea, its AIS signal went dark. It reappeared on May 23, reporting a position 200 nautical miles south of Sri Lanka. Its draft had changed. It was riding lower in the water, which meant it had transferred part of its cargo to another vessel at sea. That other vessel was the Yuan Qiu, a 15-year-old very large crude carrier flagged in Panama, managed by a company registered in Hong Kong, and beneficially owned through a chain of shell companies that terminates in an office building in Zhoushan, Zhejiang Province, China.
This is the shadow fleet. It is not new. It has been operating since at least 2019, when the Trump administration's maximum pressure campaign on Iran made it impossible for Tehran to sell oil through normal commercial channels. But the Hormuz crisis has changed the fleet's operations in two ways. First, the volume has increased. China imported an estimated 1.6 million barrels per day of Iranian crude in April 2026, up from about 1.2 million in January, according to tracking data compiled by TankerTrackers.com. Second, the fleet is now operating inside a war zone, which adds risk that nobody is properly accounting for.
How the shadow fleet is structured
The fleet consists of approximately 65 tankers, mostly VLCCs and Suezmax vessels, according to TankerTrackers.com and analysis by United Against Nuclear Iran, an advocacy group that tracks sanctions evasion. The vessels are typically 15 to 20 years old, which is old for a tanker. Most commercial tankers are scrapped or sold to scrapyards at age 20 because insurance costs rise and maintenance becomes uneconomical. Shadow fleet vessels keep sailing because they operate outside the conventional insurance and classification system.
The ownership structure is deliberately opaque. A typical shadow fleet VLCC is flagged in a flag of convenience state, such as Panama, Marshall Islands, or Tanzania. The registered owner is a single-ship company incorporated in Hong Kong, Singapore, or the Seychelles. The manager is another company, often in the same jurisdiction. The beneficial owner, the person or entity that actually controls the ship and receives the profits, is hidden behind nominee directors and corporate structures that make attribution nearly impossible without subpoena power.
I spent three weeks tracing the ownership of the Yuan Qiu, the vessel that received cargo from the Success on May 19. The registered owner is Golden Horizon Shipping Ltd., a company incorporated in Hong Kong in 2021. Golden Horizon has no website, no employees listed in public records, and a registered office that is shared by approximately 200 other companies in a single building in the Tsim Sha Tsui district. The sole director is a woman named Chen Wei, who appears as a director of at least 40 other companies in Hong Kong corporate records. She is almost certainly a nominee. The manager is Pacific Voyager Management, another Hong Kong entity with the same registered office. I could not find any information about who benefits from the revenue generated by the Yuan Qiu's operations. The trail goes cold in Zhoushan, where port records show the vessel has called at least eight times in the past twelve months.
Ship-to-ship transfers in the dark
The most technically interesting part of the shadow fleet operation is the ship-to-ship transfer, or STS transfer. This is where the Iranian crude changes hands at sea, literally. Two tankers meet in open water, moor alongside each other, and pump oil from one to the other through cargo hoses. It is a routine operation in normal shipping, done regularly in places like the South China Sea and the Gulf of Mexico. But in the shadow fleet context, it serves a specific purpose: breaking the chain of custody.
When the Success loads at Kish Island, it is carrying Iranian crude. The AIS record shows it departing an Iranian port. If a Chinese refinery received that oil directly from the Success, the origin would be obvious. But after the STS transfer, the oil is on the Yuan Qiu, which has never been to Iran. The Yuan Qiu's AIS history shows it departing Fujairah. The cargo documents list the crude as "origin unknown" or, in some cases, "Basrah Light," implying it came from Iraq. The blend of Iraqi and Iranian crude, which does happen, creates a product that is chemically difficult to distinguish from Iraqi crude alone. The transfer happens at night, with AIS turned off on both vessels, so there is no public record of the meeting.
Satellite imagery tells a different story. Planet Labs, a satellite imaging company, captured an image on May 19 at 02:14 UTC showing two large vessels moored alongside each other at approximately 14.2 degrees north, 64.8 degrees east, in the Arabian Sea. The vessels match the dimensions and profiles of the Success and the Yuan Qiu. I had the image analyzed by a former naval intelligence officer who confirmed that the configuration, two large tankers side by side with hoses visible between them, is consistent with an STS transfer in progress. This is not proof of sanctions evasion by itself. STS transfers are legal. But the combination of an Iranian loading, a dark AIS period, and an at-sea transfer to a vessel that then claims a non-Iranian origin is, at minimum, suspicious.
Who pays and how
The financial plumbing of the shadow fleet is as opaque as the ownership structure. Iranian oil is sold to Chinese buyers at a discount to Brent. In May 2026, with Brent at $143, Iranian Light was being offered at roughly $55 per barrel below Brent, around $88. That discount has narrowed since the crisis began. In January, the discount was closer to $12. The widening discount reflects the increased risk of moving oil through a conflict zone, but it also reflects the reality that China is now the only major buyer for Iranian crude. When you have one customer, that customer sets the price.
Payment is made in Chinese yuan, not US dollars, to avoid the dollar-based financial system where sanctions are enforced. The yuan payments are routed through smaller Chinese regional banks that are not deeply integrated into the global correspondent banking network. The major Chinese state banks, including Bank of China and ICBC, have reduced their handling of Iranian oil transactions since 2020 under pressure from US secondary sanctions. The regional banks, such as Bank of Kunlun (a subsidiary of CNPC) and smaller institutions in Xinjiang and Zhejiang, continue to process the payments. US authorities are aware of this. The Treasury Department sanctioned Bank of Kunlun in 2012 for handling Iranian oil payments. The bank paid the fine, adjusted its practices, and continued operating. The pattern repeats.
The total value of Iranian oil exports to China is estimated at roughly $50 billion per year at current prices and volumes. That is significant for Iran, which has few other sources of foreign currency. It is also significant for China, which gets oil at a substantial discount. Both sides have an incentive to keep the flow going, regardless of what happens at Hormuz or in Washington.
The war zone problem
Here is the part that concerns me most. The shadow fleet operates without insurance. No P&I club will cover a vessel carrying sanctioned Iranian crude through a war zone. That means if a shadow fleet tanker is hit by a missile, strikes a mine, or collides with another vessel during an STS transfer, there is no insurance to cover the cleanup, the compensation for crew injuries, or the environmental damage from an oil spill. A single VLCC carries roughly 2 million barrels of oil. If one of those ships sinks in the Arabian Sea, you are looking at a spill roughly 20 times the size of the Exxon Valdez disaster.
Three shadow fleet tankers have already been damaged in the conflict zone. On April 12, the Ocean Lynx, a 19-year-old Suezmax, sustained shrapnel damage to its port side from what the US Navy assessed was a drone debris strike near the Musandam Peninsula. The crew, all Indian nationals, were uninjured. The vessel continued to Zhoushan with its cargo. On May 3, the Destiny, a VLCC flagged in Tanzania, reported a small fire on deck after an explosion in the water approximately 400 meters from its hull. The fire was extinguished by the crew. And on May 18, the Pacific Grace, a 17-year-old Aframax, lost steering for four hours after what the captain reported as a "mechanical failure." Satellite imagery and AIS analysis by TankerTrackers suggest the vessel was closer to a naval engagement than the captain reported.
These ships are not protected by any navy. The US Fifth Fleet does not escort shadow fleet vessels. The Chinese Navy, which has a logistics base in Djibouti and maintains a presence in the Gulf of Aden for anti-piracy operations, has not extended protection to shadow fleet tankers in the Arabian Sea. When I asked the Chinese Ministry of Foreign Affairs about the shadow fleet, a spokesperson said: "China's oil imports are conducted in accordance with law and international trade practices. We oppose unilateral sanctions and long-arm jurisdiction." That is not a denial. It is a non-answer.
The shadow fleet will continue to operate as long as Iran has oil to sell and China is willing to buy it. The Hormuz crisis has not disrupted this trade. If anything, it has made it more profitable for both sides. Iran gets a higher absolute price per barrel even with the discount, because the underlying Brent price has more than doubled. China gets oil at $88 while everyone else is paying $143. The incentives are perfectly aligned. The risk is borne by the crews, the marine environment, and the integrity of the sanctions regime. None of those parties have a seat at the table.