Summer 2025 Iran Tanker Tracker: June, July, August

Between June and August 2025, Iran’s shadow fleet maintained steady average oil exports in excess of 1.6 million barrels per day (bpd). This occurred in spite of the direct military conflict with Israel during the ‘Twelve Day War’ from June 13 to June 24, which culminated in the bombing and severe degradation of Iran’s key nuclear enrichment sites. During these summer months, ship-to-ship (STS) operations in waters off Eastern Johor, Malaysia—often involving blacklisted or reflagged tankers—were central to evasion. Despite the most extensive package of shipping-related sanctions imposed by the U.S. Department of Treasury Office of Foreign Assets Control (OFAC) since 2018, illicit flows persisted, underscoring the urgent need for coordinated maritime, financial, and technological efforts to close remaining loopholes.

UANI Data For June-August 2025

UANI tracked an estimated total of 150 billion barrels (averaging 1,631,219 barrels per day) in physical exports out of Iran during the period of June through August 2025, with an estimated total value of $10.47 billion.

Ship-to-ship (STS) transfers, often involving vessels subject to international sanctions, have continued off the coasts of Singapore and Malaysia, particularly in lightly regulated waters near the Riau Islands and the Eastern Out of Port Limits (EOPL) area. Despite increased enforcement efforts by the United States, Iran has adapted its tactics, discovering new methods to transport oil more covertly. 

A recent notable trend is the sustained use of STS transfers combined with frequent Automatic Identification System (AIS) transponder manipulation and the reflagging of vessels to evade detection and sanctions enforcement—highlighting the persistent subterfuge of Iran’s shadow fleet in adapting to ever-tightening maritime controls.

Iran’s maritime sanctions evasion tactics have also reached new levels of complexity, leveraging networks of front companies, opaque ownership structures, and sophisticated concealment techniques to undermine global enforcement efforts.

UANI remains vigilant in monitoring these developments and urges the global maritime, financial, and regulatory sectors to enhance cooperation, strengthen due diligence, and support multinational enforcement efforts. Only through coordinated regional and international action can the full spectrum of threats posed by Iran’s dark fleet—to global security, environmental safety, and the rule of maritime law—be effectively countered.

U.S. Sanctions Activity

On June 6, 2025, OFAC intensified its crackdown on Iran’s illicit oil trade and financing networks by sanctioning a shadow banking architecture of more that 35 individuals and entities who were involved in money laundering for sanctioned oil sales. At the center of this network were three Iranian brothers—Mansour, Nasser, and Fazlolah Zarringhalam—who operated Iranian exchange houses and controlled a suite of foreign front companies in China, Hong Kong, the UAE, and Turkey. These actions block the assets of the designated persons and prohibit U.S. entities from any dealings with them, striking at the financial infrastructure that supports illicit Iranian oil exports, weapons programs, and destabilizing activities across the region.

At the same time, the U.S. Department of the Treasury’s Financial Crimes Enforcement Network (FinCEN) issued an updated Advisory designed to help U.S. and global financial institutions recognize and report suspicious transactions connected to Iranian illicit finance. This Advisory features detailed descriptions of common forms of Iranian financial activity used to evade sanctions—including large-scale oil smuggling, shadow banking operations, and procurement of weapons or dual-use goods. It also outlines new red flags and transaction typologies, such as the use of inconsistent documentation, fake invoices, involvement of vessels formerly owned or operated by designated persons, irregular transactions, and financial flows tied to opaque front companies. 

On July 30, OFAC announced extensive Iran-related sanctions, targeting a corrupt shipping empire controlled by Mohammad Hossein Shamkhani, son of Ali Shamkhani, a top political advisor to Iran’s Supreme Leader. UANI had publicly called for sanctions against Shamkhani and his network as early as February 2024, highlighting his central role in orchestrating Iran's illicit oil trade and maritime sanctions evasions. 

This extensive sanctions package designated more than 50 individuals, entities, and over 50 vessels involved in a network that transports Iranian and Russian oil and petroleum products worldwide, generating tens of billions of dollars in profit. Entities sanctioned include UAE-based ship management firms including Marvise SMC DMCC and Armada Global Shipping DMCC, alongside shipping and trading firms that support the Shamkhani network’s operations and financial transactions. Fourteen vessels listed on UANI’s dark fleet have also been sanctioned under this latest action. Now-sanctioned vessels within this shadow fleet include VANI (IMO 9264881) and KANTI (IMO 9282106), both implicated in transporting Iranian oil while circumventing international restrictions.

On August 21, 2025, OFAC imposed additional sanctions to further disrupt Iran’s oil exports and cut off funding for terrorism and weapons programs. The action targeted Greek national Antonios Margaritis, his network of companies, and nearly a dozen vessels that have played key roles in Iran’s shadow fleet operations. Seven vessels listed on UANI’s dark fleet—including ARES (IMO 9174397) and GIANT (IMO 9238868)—were targeted under this latest round of sanctions. 

These actions all reflect President Trump's renewed "maximum pressure" campaign against Iran, formally reinstated in February 2025 through National Security Presidential Memorandum-2 (“NSPM-2”). The goal remains: cut Iran’s oil exports—and with them, its capacity for destabilization—completely. Despite intensified sanction efforts, Iran’s oil exports—largely destined for China—continued unabated throughout July 2025, providing a vital revenue lifeline that sustains the Iranian regime.