Aramco, ADNOC run tankers through Hormuz with AIS off as blockade hardens

Saudi Aramco Trading and Abu Dhabi National Oil Company have moved a small number of crude and LNG cargoes through the Strait of Hormuz in recent days by switching off vessel transponders and conducting ship-to-ship transfers in Omani waters, Bloomberg reported Friday. The maneuver — long associated with Iranian and Venezuelan sanctions evasion — is being adopted by the two largest legitimate Gulf exporters as Iranian threats and US Navy interdictions strip the strait of normal commercial traffic.

Bloomberg, citing ship-tracking data and people familiar with the cargo movements, reported that at least two LNG carriers loading at Das Island went dark on automatic identification system feeds for portions of their transit, and that the supertanker Basrah Energy completed a ship-to-ship transfer outside Iranian waters before its cargo continued onward. Non-Iranian crude exports through Hormuz have collapsed to roughly 500,000 barrels per day, against a pre-war baseline of 13.6 million barrels per day — roughly four percent of normal throughput.

The episode crystallizes how thoroughly the Iran-US confrontation has rewritten Gulf shipping practice. Producers that have spent two decades building reputations on transparent, transponder-on, fully insured deliveries are now operating like the smuggling networks they once helped sanction.

The mechanics: dark transits and Omani transfers

According to Bloomberg’s reporting, the going-dark pattern follows a consistent template. Vessels loaded at Saudi or Emirati terminals approach the strait, switch off AIS transponders inside or just before Iranian-claimed waters, and either accelerate through the chokepoint or rendezvous with a second tanker in Omani territorial waters for a ship-to-ship transfer. The receiving vessel — typically not connected to either originating producer — then carries the cargo onward to Asian buyers.

Bloomberg identified the supertanker Basrah Energy as having completed one such transfer, and named two Das Island LNG carriers among the vessels that went dark on tracking feeds. AIS is required by the International Maritime Organization for vessels above 300 gross tons on international voyages, and switching it off is permitted only in narrow safety circumstances. Routine commercial transits with transponders off are, in normal times, a regulatory and insurance violation rather than an option.

Aramco and ADNOC did not comment in Bloomberg’s report.

Why now: Navy interdictions and an Iranian toll regime

The dark-transit pattern emerged in the wake of two parallel pressures on Hormuz traffic. US Navy forces have been disabling Iranian tankers caught moving sanctioned crude, most recently the Sea Star and Sevda, after Iran seized commercial vessels in the Gulf of Oman. From the opposite direction, Iran has stood up a Persian Gulf Strait Authority demanding transit tolls of up to two million dollars per vessel, a fee structure that creates immediate exposure to US secondary sanctions for any operator that pays.

That two-sided squeeze has left commercial shipping with no clean route. Paying the Iranian toll triggers OFAC liability; refusing it risks IRGC boarding. Transiting visibly invites Iranian challenge; transiting dark violates IMO rules and standard P&I insurance terms.

The pressure intensified Saturday. The Islamic Revolutionary Guard Corps vowed a “heavy assault on American centers” if US forces strike additional tankers, according to wire reporting carried by CNN. Earlier in the week, the United Arab Emirates intercepted two ballistic missiles and three Iranian drones over its territory, NPR reported, citing Emirati defense officials — a strike pattern that put ADNOC’s home country directly in the line of fire and almost certainly factored into the calculus around dark transits.

The volume picture

The numbers reported by Bloomberg are the most concrete evidence yet of how badly the strait has been throttled. Roughly 500,000 barrels per day of non-Iranian crude is moving through Hormuz, against a 13.6 million bpd pre-war baseline. That is a 96 percent collapse in legitimate transit volume from the world’s most important oil chokepoint.

Tanker insurance is the binding constraint. Lloyd’s of London syndicates have effectively suspended new war-risk coverage for Hormuz transits pending clarity on whether OFAC will treat Iranian toll payments as material support for a designated terrorist organization. Without coverage, most charterers cannot legally move cargo — which is the proximate reason Aramco and ADNOC appear to be improvising around the system rather than working through it.

Ship-to-ship transfers in Omani waters add cost and time but accomplish two things: they break the chain of custody before insured cargo reaches Iranian-claimed waters, and they distribute legal exposure across multiple vessels and operators. It is the same architecture Iranian and Venezuelan exporters have used for years to move sanctioned barrels.

Market reaction: Brent steady, gold at a record

Brent crude settled around $101.29 Friday, holding within the narrow range it has traded since the Hormuz crisis began. The price stability masks a sharp divergence between paper and physical markets — futures contracts reflect ample global inventory while physical Asian buyers are paying significant premiums for delivered cargoes that actually arrive.

Gold told a different story. Spot prices touched a record $4,709.89 per ounce Friday, according to Voice of Emirates citing Reuters wire data, as traders priced in a combination of war-risk hedging and optimism that the US-Iran memorandum of understanding could move toward resolution. Defense ETFs traded heavy on the same logic, as the war-premium that had bid up contractor shares began fading into the possibility of a diplomatic settlement.

Diplomatic backdrop

The Trump administration’s 14-point Project Freedom Plus framework remains the open diplomatic channel. Tehran’s formal response is overdue; Iran’s parliament has publicly dismissed earlier US proposals, while the IRGC’s Saturday threats reinforce the hardline faction’s posture. Whether the MOU advances or collapses will determine whether the Hormuz crisis enters a managed wind-down or a longer phase of squeezed, semi-clandestine shipping.

What dark-AIS shipping means

The compliance implications run in two directions. P&I clubs — the mutual insurers that cover most of world tonnage — write policies that require AIS to remain on except in narrow safety circumstances. Routine dark transits puncture coverage. If Aramco and ADNOC cargoes are moving uninsured or under bespoke arrangements, the loss exposure on any single incident is enormous.

OFAC faces its own question. US sanctions architecture has spent a decade treating dark-AIS transits as a hallmark of sanctions evasion, with secondary sanctions reaching insurers, classification societies, and port state authorities that touch the cargo. Applying that doctrine consistently would mean treating Saudi and Emirati state-owned exporters the same way Treasury treats Iranian and Venezuelan smugglers — a politically untenable outcome that the United States is unlikely to pursue. The likelier path is a quiet carve-out, formalized or not, that recognizes Gulf allies operating under duress.

Closing: a baseline that may become standard

Roughly 500,000 barrels per day is approximately four percent of pre-war Hormuz throughput. The cargoes Bloomberg identified are real and are arriving at destination, but at a volume that does not begin to replace the lost capacity. The Kharg Island oil slick documented in satellite imagery this week suggests Iranian export infrastructure has taken damage that further constrains supply on the other side of the ledger.

If the MOU framework holds and the strait reopens to transparent commercial traffic, the dark-transit episode becomes a footnote — a brief period in which Gulf majors borrowed Iranian techniques to keep barrels moving. If it collapses, Bloomberg’s reporting documents what could become the new baseline: legitimate Gulf exporters operating under the same opacity their sanctioned competitors have used for years, with all the insurance, regulatory, and accounting consequences that follow.