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Public shipping maps make the Strait of Hormuz look almost closed. They are misleading. Saudi tankers are crossing with their tracking systems switched off, millions of barrels are being transferred between ships outside the Gulf, and specialist maritime trackers are finding far more traffic than appears on ordinary AIS screens.
Iran’s latest proposal would begin a seven-day process towards reopening the Strait of Hormuz if the United States lifts its naval blockade of Iranian ports, allows Iranian oil exports and accepts a wider ceasefire, after which negotiations would resume. President Donald Trump rejected the proposal on September 26. The timing matters because Washington has been arguing publicly that enough energy is still moving through the Gulf to prevent the disruption from becoming an immediate economic crisis. On August 28 the White House claimed that nearly 1,500 commercial vessels had passed through under American protection carrying 750 million barrels of crude, and that Gulf oil exports had recovered to two-thirds of their pre-operation level. Those are US government claims rather than independent measurements, but they make the administration’s position clear: Washington believes it can withstand prolonged disruption. White House, August 28; US Government Publishing Office.
The traffic is larger than the public AIS picture
Lloyd’s List Intelligence provides the clearest independent evidence that visible AIS traffic understates the amount of shipping actually using Hormuz. Its September 24 briefing counted 104 preliminary non-Iranian-linked transits during September 14 to 20, including 82 tanker and gas-carrier movements. Lloyd’s said the total could rise as further dark passages were verified, and found that Saudi-owned or Saudi-flagged vessels had crossed more often during the first three weeks of September than in any full month since the war began. Much of the increase came from Bahri very large crude carriers travelling with AIS switched off. Lloyd’s nevertheless said the threat to commercial shipping remained severe and that there was still no return to normal traffic. Lloyd’s List Intelligence, September 24.
Kpler’s figures show how the workaround has developed outside the strait. Gulf of Oman ship-to-ship transfers averaged only 0.16 million barrels a day in 2025, but Kpler says they have averaged 3.7 million barrels a day since the US-Iran war began and were running at a record 7.2 million barrels a day in September. That is not the same as physical Hormuz throughput because some cargoes can be transferred more than once, but it shows the scale of the new system. Kpler says transfer capacity around Fujairah and Sohar is approaching practical limits and estimates that moving an additional three million barrels a day of Saudi crude through the system could require another 36 to 40 VLCCs under its base case. Kpler, September 21.
The tankers identified in the Saudi loading surge
One of the clearest vessel-level reconstructions comes from Kpler Risk and Compliance data published by DataPortuaria. Six VLCCs loaded nearly 12 million barrels at Ras Tanura and Juaymah on September 21. Four had entered the Gulf between September 15 and 17 in ballast and declared Ras Tanura as their next port. Three of the six had already been involved in dark ship-to-ship transfers or dark port calls during the previous six weeks. DataPortuaria/Kpler Risk and Compliance, September 22.
| Tanker | Recorded activity |
|---|---|
| Gold Shine IMO 9519717 |
Bahri VLCC; entered the Gulf in ballast between September 15 and 17 declaring Ras Tanura as its next port, then joined the September 21 loading operation. |
| Silver Shine IMO 9421415 |
Bahri VLCC; dark port call at Al Basrah on September 8, dark ship-to-ship transfer with Maran Athena off Fujairah on September 14, then loaded again at Ras Tanura on September 21. |
| Diamond Shine IMO 9384239 |
Bahri VLCC; entered the Gulf in ballast between September 15 and 17 declaring Ras Tanura as its next port, then joined the six-vessel loading surge. |
| Maharah IMO 9779812 |
Bahri VLCC; entered the Gulf in ballast during the same period declaring Ras Tanura as its next port, then joined the September 21 loading operation. |
| Peru Prosperity IMO 9418066 |
Dark ship-to-ship transfer with Izki at Sohar on August 25, dark call at Ras Tanura on August 31, then returned to load there on September 21. |
| Egypt Prosperity IMO 9534004 |
Dark ship-to-ship transfer with Degas at Sohar on August 15, followed by a dark call at Al Basrah Oil Terminal, then joined the September 21 Saudi loading surge. |
Public AIS records substantially understate traffic because many vessels are travelling dark, while satellite imagery, later AIS reappearances and cargo records allow some voyages to be reconstructed. DataPortuaria found that 25 of 26 inbound ballast crude-tanker crossings recorded between September 12 and 20 were classified as route-undetermined movements, while 46 of 47 crossings fell into the same category during the previous nine days. In wartime conditions an AIS gap does not by itself prove deception; ships may alter their broadcasts because of the risk of attack, interception or navigation hazards. DataPortuaria/Kpler Risk and Compliance.
An expensive wartime corridor
The extra traffic has not restored normal shipping. The International Maritime Organization had confirmed 85 maritime incidents in the Strait of Hormuz and the wider Middle East by September 24. Recent cases included the Cape Dao, damaged northeast of Khasab on September 23 with one seafarer killed; the LR Stephanie, damaged in the strait on September 21 with two crew injured; and the Al Maryah, also damaged in the strait on September 21. International Maritime Organization.
The system now operating around Hormuz is therefore a wartime corridor rather than a restored commercial route. Tankers prepared to enter the Gulf can load crude, cross the dangerous section of the route and transfer their cargo to another vessel outside the strait, allowing the first ship to return for another load instead of spending weeks sailing to Asia and back. It uses more tankers, consumes more time and raises freight and insurance costs, but it keeps part of the Gulf’s oil flow moving.
Iran has sharply reduced and disrupted traffic through Hormuz, but it has not stopped Gulf energy exports. Saudi crude, Iraqi oil and some Gulf gas are still moving, often through a system of dark passages, shuttle voyages and ship-to-ship transfers that is far more expensive and dangerous than normal commercial traffic. The result is a strait that remains strategically important but is no longer functioning as a complete energy chokehold.
Iran’s seven-day proposal therefore arrives at a moment when Washington may believe it can afford to wait. Hormuz remains dangerous, expensive and severely disrupted, but state-backed tanker fleets are still moving cargo, some vessels are crossing with AIS switched off, and ship-to-ship transfers outside the Gulf are keeping part of the export system alive. None of this restores normal shipping, but it may be enough to prevent disruption of the strait from becoming the immediate economic crisis Tehran hoped would force Washington towards an agreement.