Since the US blockade in the Gulf of Oman began last month, at least 13 tankers have offloaded Iranian oil in clandestine ship-to-ship transfers. thousands of miles awaynear a group of small islands in Indonesia known as the Riau Archipelago, according to a Washington Post analysis of satellite images and ship tracking data. According to experts, these transfers are part of a secret agreement that for years has allowed Tehran to continue selling oil despite crushing international sanctions.
Although the blockade seems to have stopped the departure of new shipments of Iranian oil from the Persian Gulf, The ongoing transfers allow Tehran to keep that source of revenue open, if only temporarily, while shipments already at sea head to China or other markets. Satellite images taken since April 16 showed six loaded tankers sailing under the Iranian flag docking alongside six empty tankers. Seven other loaded tankers — apparently sailing under false flags or whose management had not been revealed, according to maritime information repository Equasis — were captured on images alongside other empty vessels.
According to oil tracking company TankerTrackers, the 13 vessels unloaded about 22 million barrels of Iranian crude, an amount that could be worth more than $2 billion at current market prices. Based on the sequence of events, the company determined that oil transfers had occurred and the loaded tankers were left empty and the empty tankers were loaded. According to the maritime intelligence company Windward, the Riau archipelago, on the route between the Middle East and China, has long served as a staging point where ships stealthily exchange Iranian oil to conceal its origin.
According to the US government, China buys more than 90% of Iranian oil, at a deep discount, but still generate revenues that represent almost half of the Iranian government’s budget. Satellite images are one of the few ways to determine whether such a transfer has occurred, since the tankers involved rarely reveal their location. According to the U.S. Office of Foreign Assets Control, a single shipment of Iranian oil can undergo multiple transfers between ships on the high seas before reaching its destination.
The vessels involved often have opaque registration information or fly false flags. According to the global intelligence firm Kpler, around 42 million barrels of Iranian oil remain on board tankers near the Riau archipelago, a figure much lower than the almost 90 million recorded in early February. “For now, reserves are available. They are not being replenished,” the firm said in a report published Wednesday. “Ultimately, the longer the blockade lasts, the fewer shipments Iran will have to send to China,” said Michelle Wiese Bockmann, senior analyst at Windward.
Financial details related to the sale of oil transferred from ship to ship, including the exact date Tehran receives payment, are often opaque and sometimes deliberately hidden, said Petras Katinas, an energy researcher at the Royal United Services Institute, a London-based defense and security think tank. Some buyers appear to pay partially in advance, while others settle the payment once the tanker reaches territorial waters or after it arrives at port, he explained. Three days after the start of the blockade, The US Navy expanded its operations against exports Iranians beyond the Middle East.
By doing so, officials say, U.S. forces have the authority to detain any ship linked to Iran or suspected of carrying cargo that could benefit the Iranian government, regardless of its location. The Defense Department referred questions about ship-to-ship transfers to the White House. “The energetic US military blockade has forced more than 50 ships to turn around or return to port, which has contributed to the resounding success of Operation Economic Fury,” White House spokeswoman Anna Kelly said in a statement. “As a result, the Iranian economy is completely strangled, and President Trump has everything to gain as negotiators work to reach a deal,” he said.
The White House did not respond to a question about whether the ships involved in the transfers observed by The Post are considered subject to the expanded restrictions. Grant Rumley, specialist in Middle East security dThe Washington Institute for Near East Policy said planners must prioritize how best to pressure Iran with limited resources. “Ultimately, it’s about weighing the pros and cons,” Rumley said. “Intercepting all Iranian oil shipments requires time and resources that could be used to maintain the blockade.” Two weeks ago, US forces boarded the Tifani and Majestic X oil tankers in the Indian Ocean. According to experts, the ships had made transfers near the Riau archipelago in recent months and were probably heading there when they were intercepted.
Both were carrying Iranian crude oil, according to TankerTrackers. “We will continue to carry out similar maritime interdiction actions and activities in the Pacific and Indian Oceans against Iranian ships and Dark Fleet vessels,” said General Dan Caine, chairman of the Joint Chiefs of Staff, at a press conference, after the vessels were seized. Since April 16, five additional Iranian-flagged tankers have arrived near the Riau archipelago loaded with Iranian oil, according to satellite images and ship tracking data. Although these images do not show the unloading of its cargo, one of them sailed west and is empty, according to TankerTrackers. It is not clear if the other vessels have unloaded. To get there from the Gulf of Oman, ships typically sail through the Strait of Malacca, a busy sea passage between Malaysia and Indonesia.
Ships are required to broadcast their locations as they transit the strait, allowing brief, if infrequent, glimpses of tankers that normally keep their transponders turned off. According to Windward, as of Monday no large tanker carrying Iranian oil had transited the Malacca Strait in 10 days, the longest period without any crossing since the war began.
Over the weekend, two Iranian oil tankers apparently headed for the Riau archipelago avoided the Malacca Strait, traveling for several days south and east toward Australia before turning north and passing through the Lombok Strait near Bali, according to satellite images and ship tracking data. This change suggests that ships carrying Iranian oil are diverting their route to avoid the Strait of Malacca, where visibility is greater, despite the increase in travel time. “Lombok is not improvisation,” Kpler stated in his report. “It is the next step in a deliberate adaptation.”