On a normal day, roughly 60 to 80 commercial vessels pass through the Strait of Hormuz, the 21-mile-wide corridor between Iran and Oman that carries about a fifth of the world’s oil supply. In late April 2026, that number dropped to five.
The near-total freeze in traffic followed Iranian attacks on three ships in or near the strait on April 22, according to Associated Press reporting that tracked the strikes and their aftermath using maritime data. The assaults included vessel seizures and at least one direct strike, and they produced an immediate chilling effect. Within 24 hours, commercial transits collapsed to a level that amounts to a functional shutdown of one of the most important waterways on the planet.
What happened on April 22
Iranian forces targeted three vessels in a concentrated burst of aggression that reshaped the security picture overnight. The AP confirmed the attacks through cross-referenced maritime tracking data and on-the-ground accounts. The strikes did not just reduce the number of ships willing to enter the strait. They also changed how the remaining vessels moved.
Some ships were pushed into an Iranian-controlled corridor, effectively ceding route selection to Tehran. That forced rerouting compressed traffic into a narrow lane, raising the risk of bottlenecks and secondary incidents in waters already under military threat. For shipping companies weighing whether to send their next tanker through Hormuz, the message was blunt: comply with Iranian terms or stay away.
The U.S. Energy Information Administration estimates that roughly 21 million barrels of oil per day flow through the strait under normal conditions, representing about 20% of global petroleum consumption. Even a short disruption at that scale sends shockwaves through energy markets, and the April 22 attacks were anything but subtle.
Ships are faking their identities to avoid attack
In the days following the strikes, analysts at Kpler, a commodity data intelligence firm, identified a troubling new pattern: commercial vessels in the region began manipulating their Automatic Identification System broadcasts to present themselves as Chinese. Ships altered AIS destination fields or changed their broadcast behavior to signal alignment with Beijing, a country Iran has indicated it will not target.
The tactic, documented through analysis of AIS data reported by the AP and confirmed by MarineTraffic tracking records, tells us something important even beyond the deception itself. Commercial operators view the threat environment as severe enough to take active countermeasures, a signal that the shipping industry considers the strait functionally hostile to non-Chinese-flagged traffic.
The spoofing also degrades the reliability of vessel tracking systems. If ships are broadcasting false identities and altered destinations, the true volume and nationality breakdown of traffic through Hormuz becomes harder to assess. That uncertainty cuts both ways: the actual number of transits in any given 24-hour window could be somewhat higher or lower than what tracking platforms recorded.
What we still do not know
The five-ship figure, while striking, comes with important caveats. No official transit count has been released by the International Maritime Organization, the U.S. Navy’s Fifth Fleet, or regional port authorities. The number is derived from commercial maritime tracking platforms that rely on AIS broadcasts, the same broadcasts that ships in the area are actively manipulating. MarineTraffic data is widely used and generally reliable, but it was never designed to function as a definitive census during an active military crisis.
The identity of the five ships that did transit has not been publicly confirmed. Whether they were loaded crude tankers, empty freighters, or military escorts matters enormously for calculating the real economic impact. Five supertankers carrying two million barrels each would represent a very different story from five vessels in ballast.
Iran’s own position remains opaque. No statements from Iranian officials have appeared in English-language reporting reviewed for this article to confirm the operational details of the controlled corridor or to explain what criteria Tehran is applying to decide which ships may pass. Without that clarity, it is difficult to determine whether the corridor represents a deliberate assertion of territorial control, a temporary wartime measure, or an improvised response to specific military objectives.
Perhaps the most consequential unknown is duration. The five-ship count reflects a single 24-hour snapshot. Whether traffic rebounds or remains suppressed depends on the pace of military escalation, decisions by major carriers like Maersk and MSC about rerouting vessels around the Cape of Good Hope, and how quickly war-risk insurance premiums climb to levels that make Hormuz transits economically unviable.
Why this is coercion, not a blockade
Iran did not formally close the Strait of Hormuz. What it did was arguably more effective in the short term: it attacked selectively, forced surviving traffic into a lane it controls, and created conditions where most operators chose to stay away on their own. A declared blockade would trigger well-established legal and military responses under international law. A de facto choke on traffic achieved through targeted violence and intimidation is harder for outside powers to confront without risking a wider war.
That distinction shapes how governments, militaries, and markets will respond in the coming weeks. The U.S. Fifth Fleet, headquartered in Bahrain just inside the Persian Gulf, has not publicly announced convoy escort operations or freedom-of-navigation patrols in response to the attacks, though such measures have been deployed in past Hormuz crises, including during the 1987-1988 tanker war with Iran.
Oil markets, meanwhile, respond to expectations as much as to physical supply disruptions. The psychological weight of a five-ship day at Hormuz could prove as significant as the barrels actually delayed, particularly if traders conclude that the disruption is likely to persist or escalate. But precise supply-loss calculations require vessel-level data that is not yet available.
What to watch next
Three factors will determine whether this episode remains a sharp but contained shock or marks the beginning of a sustained crisis.
First, insurance. War-risk premiums for Hormuz transits will almost certainly spike in the days ahead. Those costs flow directly into freight rates and, eventually, into fuel and consumer goods prices. Businesses with supply chains running through the Persian Gulf should be reviewing contingency routing now. The window between a one-day disruption and a sustained blockade can close faster than logistics teams can adapt.
Second, military posture. Whether the U.S., U.K., or coalition partners move to escort commercial vessels through the strait will signal how seriously Western governments assess the threat. The absence of escort operations so far leaves shipping companies to make their own risk calculations, and most appear to be choosing caution.
Third, Iran’s next move. If the April 22 attacks were a one-off demonstration, traffic may gradually recover as operators test the waters. If Iran continues targeting vessels or tightens control over its corridor, the strait could remain functionally closed to non-compliant shipping for an extended period.
For now, the available evidence supports three conclusions. Security conditions for commercial shipping in and around the Strait of Hormuz have deteriorated to the point that most operators are unwilling to sail without additional protection. The information environment is clouded by deliberate AIS manipulation and the absence of official transit data, meaning early numbers should be treated as directional signals rather than precise counts. And the episode has demonstrated, with uncomfortable clarity, how quickly a small number of targeted attacks can paralyze a waterway that underpins the global economy.
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*This article was researched with the help of AI, with human editors creating the final content.
