An unconventional oil transportation system is quietly operating in the Gulf of Oman against the backdrop of the Strait of Hormuz being blocked by Iran. Based on multiple sources, Reuters reports that the US military has spearheaded the establishment of a large-scale ship-to-ship transfer network to sustain crude oil exports from the Gulf region. This method has long been a classic tactic used by Iran to evade sanctions.
As many as eleven informed sources have confirmed to Reuters that this operation commenced in early May 2026, with at least 116 vessels participating to date. The transfers are concentrated primarily at two locations: offshore from Fujairah in the United Arab Emirates and in waters near the port of Sohar in Oman, both areas close to the exit of the Strait of Hormuz.
Satellite imagery indicates the intensity of operations is steadily increasing. Footage reviewed by Reuters shows that just on Tuesday morning, twelve pairs of tankers were conducting transfers side-by-side in the Gulf of Oman. Eight pairs were located off the coast of Sohar, with four pairs distributed near Fujairah. Images from June 11th show that overall activity peaked last week, with a total of seventeen pairs of vessels operating simultaneously across both sites.
The system's operation relies on meticulous scheduling. Tankers must first wait at designated assembly points outside the strait, then enter the channel in sequence, maintaining intervals of approximately 3,000 to 4,000 meters. Multiple sources state that vessels switch off their transponders and dim their lights when passing through sensitive maritime zones to reduce the risk of detection.
Once a vessel crosses the boundary of the control area designated by Iran, it docks with a large receiving tanker to complete loading or unloading. Each transfer operation takes about 24 to 40 hours. The empty vessel then returns, while the fully loaded Very Large Crude Carrier continues its journey to international markets.
The involved methods extend beyond maritime coordination. Six individuals with direct knowledge of the operation stated that the US provides support through airborne and surface drones, helicopters, and continuous monitoring. However, no evidence has been found of direct US military involvement in the specific loading or unloading operations.
Risks associated with this operation became apparent around an incident on June 9th. Four sources, including a former US official, told Reuters that an Apache helicopter shot down by Iran that day was of a type participating in the mission. Satellite images show six pairs of tankers gathered in waters near Sohar at the time of the incident. Reuters could not confirm the specific role of that helicopter in the operation. A US Department of Defense official responded that Central Command forces were not involved in offshore ship-to-ship transfers and that the two crew members had been rescued by an unmanned surface vessel.
The security environment around the transfer network remains tense. The British maritime risk firm Vanguard reported that an "unidentified projectile" struck a tanker off the coast of Oman over the weekend, causing some cargo leakage but no environmental damage. It did not specify whether the vessel was part of the transfer operation. Simultaneously, the port of Fujairah has also come under fire from Iran.
The Strait of Hormuz typically handles about one-fifth of global oil shipments. Iran's blockade following the US-Israel conflict has caused major supply disruptions and contributed to rising global inflation. In this context, this less efficient and riskier transfer method has become one alternative path for maintaining energy flows.
US President Trump stated that, according to a US-Iran framework peace agreement announced this week, the strait is expected to reopen on Friday, but specific implementation details remain unclear. Reuters could not confirm whether the agreement would alter the current maritime transfer arrangements.
In terms of operational mode, this system bears the clear hallmarks of "gray shipping." Vessels turn off positioning systems, do not file regular reports, and use staggered sailing schedules to reduce the probability of being tracked.
Michael Froman, Chairman of the Council on Foreign Relations, noted: "As the old rules erode, the irony is that the US is now drawing from the playbooks of Russia, North Korea, and even Iran—countries whose so-called 'dark fleets' precisely pioneered these techniques to evade US and UN sanctions."
To gain access to the system, operators must undergo rigorous vetting. Four sources said applicants must submit information to the US Navy's Navigation Cooperation and Guidance Office in Bahrain, including complete voyage tracks, disclosure of beneficial ownership, and cargo documentation, and agree to inspections. Once approved, vessels are assigned transit windows and remain in communication with the office throughout their voyage.
Shipping data from LSEG and Kpler, along with multiple satellite images reviewed by Reuters, show that between May 2nd and June 11th, multiple batches of tankers repeatedly rendezvoused and conducted transfers in the aforementioned areas. Based on capacity estimates, this network may have cumulatively transferred at least 90 million barrels of crude oil and refined products. However, this volume remains significantly lower than the pre-conflict daily flow of approximately 20 million barrels through the strait.
Regarding specific participants, international tanker operators dominate the receiving end. Greece-based Dynacom Tankers Management is cited as one such participant.
Regional energy firms are also deeply involved. Multiple sources stated that the Abu Dhabi National Oil Company (ADNOC) is one of the most active participants, and the Kuwait Oil Tanker Company also plays a significant role in the operation.
However, this system introduces new risks. Due to transponders being off, restricted navigation lights, and a lack of regular reporting, multiple industry insiders point to an increased probability of ship collisions. A maritime security source stated, "There is a lack of reliable data, and companies are not reporting through regular reporting centers."
Experts are generally cautious about the long-term viability of this model. Noam Raydan, a maritime risk expert at the Washington Institute, noted that Iran could still use drones or gunboats to harass shipping at any time. "You never know when Iran might suddenly act," he said. He also emphasized that this approach is more of an emergency arrangement, stating, "I don't see this as a permanent solution. It's a temporary response in extraordinary times."
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