Iranian entities are using a shadow fleet of aging tankers to evade U.S. sanctions and maintain the flow of crude oil to foreign buyers.

This evasion network undermines U.S. efforts to restrict Iranian oil revenues, allowing the regime to sustain its economy despite an escalated push by the Trump administration to block the trade.

The fleet employs several tactics to remain undetected, including disabling Automatic Identification System (AIS) tracking and conducting ship-to-ship transfers in international waters [1, 2]. These maneuvers allow vessels to mask the origin of the cargo before routing it through busy Southeast Asian shipping lanes [1, 3].

Recent reports highlight the waters off Malaysia’s southern Johor state as a critical hub for these clandestine transfers [3]. By moving oil between ships in these regions, the network can obscure the trail of the crude before it reaches its final destination [1, 3].

A primary buyer for these illicit shipments is China. The regime has managed to sell billions of dollars [1] in crude to China using this clandestine network of aging tankers, a Hindustan Times reporter said.

U.S. authorities have increased efforts to disrupt these operations. A Financial Post analyst said the U.S. has recently escalated its push against shadow fleets, which are increasingly used by heavily sanctioned countries to skirt restrictions [2].

Despite these efforts, the scale of the operation remains significant. The use of foreign-linked vessels and aging tankers creates a layer of anonymity that makes enforcement difficult for U.S. regulators [1, 2]. Analysis from earlier this month indicates that the U.S. blockade continues to squeeze the Iranian oil industry, though the shadow fleet provides a persistent leak in the sanctions regime [4].

“The regime has managed to sell billions of dollars in crude to China using a clandestine network of aging tankers.”

The persistence of the shadow fleet demonstrates the difficulty of enforcing unilateral sanctions in a globalized maritime economy. By leveraging 'dark' shipping and regional hubs like Johor, Iran can maintain essential revenue streams, suggesting that total economic isolation is nearly impossible as long as major buyers like China are willing to engage in clandestine trade.