Are Hormuz ships more willing to defy Iran or the US? What the data shows

EXPLAINERMost ships are trying to mask their identities while trying to cross the strait. But more seem scared of Iran than of defying the US.Published On 20 Aug 2026United States President Donald Trump has insisted that his military remains in control of traffic through the Strait of Hormuz, and suggested this past week that the US might even seek to take charge of the territory.On Tuesday, he also claimed that the strait was open for vessels to pass through, despite Iranian insistence that the waterway was closed for all ships that don’t seek Tehran’s approval before transit, and even though the US itself has a naval blockade in place targeting all Iran-linked ships.At the same time, Trump has threatened to bomb Oman, a US ally that sits across the Strait of Hormuz from Iran – the waterway lies in the maritime territories of Iran and Oman – in an apparent bid to dissuade Muscat from striking any deal with Tehran to jointly manage the strait.So who really is in control of the Strait of Hormuz at the moment?Amid the claims and counterclaims from both sides, actual data on the traffic passing through the waterway offers vital clues. We break it down.What are the two main routes through the Strait of Hormuz?Before the war started, the Strait of Hormuz was largely considered a single waterway, without distinctions between “Iranian” or “Omani” routes, and ships entered and exited along well‑established traffic separation schemes, mostly along the central part of the strait.Decisions on how ships navigated the strait were determined by port calls, charter terms and safety rather than fear of military consequences.Since the war has spiked tensions between the US and Iran over the Strait of Hormuz, the waterway has been fractured into two main routes. Tehran insists on the northern, Iranian route, hugging Iran’s coast near Larak Island and Qeshm Island, and feeding directly into Iranian ports and offshore terminals.The other route is the southern, Omani route, closer to Oman and further from Iran’s shoreline. This is the route that Washington insists on, and is the one used by commercial carriers under US Naval protection.What routes do ships carrying oil and gas use?Data from maritime intelligence firm Kpler shows that 112 vessels carrying crude, liquefied petroleum gas (LPG) and liquefied natural gas (LNG) passed through the Strait of Hormuz – either entering the Gulf or leaving it – between August 1 and August 19.Of those tankers and carriers, 21 openly used the Iranian route and only two formally used the Omani route.The remaining 89 vessels, which make up more than 80 percent of the total oil and gas traffic through the strait in this period, went along dark or otherwise unclassified routes.This happens when a vessel’s movements cannot be fully tracked or clearly linked to a declared route because the vessel either turns off its Automatic Identification System (AIS) transponder or the AIS data does not neatly fit into Kpler’s defined Iranian or Omani corridors. Hence, it is not clear which route these vessels took.“While these transits can be observed once vessels reappear after crossing, the nature of dark routing makes it highly difficult to determine what proportion may also have used the Omani route or to confirm their precise routing from the available data,” Mohamed Rafik Halitim, a customer success manager for maritime and commodities at Kpler, told Al Jazeera.What about cargo beyond just oil and gas?Kpler’s data shows that 236 ships in all transited through Hormuz between August 1 and August 19. This includes not just oil and gas vessels, but others carrying dry cargo and chemicals.Of these ships, 83 openly used the Iranian route, only three publicly used the Omani route and two used the old pre-war route that ran through the centre of the strait.But the bulk of the ships, 148 of them, again went dark or used unknown routes while transiting through the strait. That’s more than six out of 10 ships that passed through Hormuz in this period.By comparison, 35 percent of vessels openly used the Iranian route, and only a handful used the Omani or pre-war route publicly.Why are so many vessels switching off their transponders?Since the beginning of the war, both Iran and the US have not only threatened, but have actually bombed vessels that they each claim are violating their routes or rules for maritime navigation through the waterway.Hence, several vessels are turning off their transponders to strip away the digital identifiers that military forces use to target them.“Switching off transponders can reduce the visibility of a vessel’s precise location and movements, although it also creates concerns about maritime safety and transparency,” Neil Quilliam, an associate fellow at the Middle East and North Africa Programme at the UK-based think tank Chatham House, told Al Jazeera. “Some operators believe the commercial and security benefits outweigh those risks under current conditions.”On August 8, the United Arab Emirates accused Iran of attacking a tanker owned by the Abu Dhabi National Oil Company (ADNOC) with a missile as it tried to pass through the strait.In a statement, ADNOC said that since the beginning of the war, 15 of its vessels had been attacked by missiles and drones while transiting the strait, killing one crew member and injuring 20. The ADNOC statement did not blame either side.Last month, the US fired on an oil tanker traversing through the strait towards Iran’s Kharg Island. The US said it fired Hellfire missiles at the ship after it ignored several warnings.On August 11, the US said a Navy helicopter also fired two Hellfire missiles at the Panama-flagged Vela Nova cargo vessel, adding that the ship was attempting to break its blockade of Iranian ports in the Gulf of Oman, which connects directly to the Strait of Hormuz.Another reason to switch off transponders is to conduct ship-to-ship cargo transfers, mid-route, without being seen, experts say.“According to sources and data over the past two weeks, some Gulf countries, including Saudi Arabia, Iraq, and Kuwait, have sent out some shipments through the Omani route by turning off their vessel tracking and by doing ship-to-ship transfers,” energy policy researcher and consultant Marc Ayoub told Al Jazeera.In essence, a ship that wants to avoid the threat of Iranian missiles would travel through the Omani route with its transponder off, but then passes its cargo over to a ship outside the strait, which then ferries it to its final destination. The original “dark” ship then returns to its port of origin undetected.Ayoub added that a number of Iranian vessels are also transiting through the Omani route – often including ship-to-ship transfers – to avoid sanctions against Iran and the US blockade.“They send their shipment to Oman through the Omani route, they change the documents of those shipments so that they appear as if they are exported by Oman, and then they send it to the oil market.”Are ships more scared of defying Iran or the US?The fact that most ships passing through the strait are switching off their transponders or using unknown routes means that it is impossible to know, for now, exactly how many are actually using either the Iranian or the Omani route.That in turn means it is difficult to conclusively say who “controls” the strait at the moment.But the data does tell us which of the two powers vessels are more willing to defy and who they’re more scared of offending.Despite a US naval blockade backed by the world’s most powerful navy, a fifth of all energy-carrying ships openly transited Hormuz through the Iranian route, defying Trump’s threats. And that number rose to 35 percent of all vessels when carriers ferrying cargo and chemicals are included.