A formal barrier across Hormuz is unnecessary. Commercial traffic depends on confidence across a chain of owners, charterers, insurers, banks, crews and port authorities. A few credible incidents can make the route economically unusable even when a channel remains physically open. |
Key facts
• Iran can hail, divert, board or seize selected ships.
• Mines or mine warnings can slow traffic and require lengthy clearance.
• Drones and shore-based missiles can attack from dispersed positions.
• AIS spoofing, jamming and route uncertainty can increase collision and attribution risks.
• Selective permission by flag, cargo or ownership can turn passage into political leverage.
Key statement
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Risk can substitute for physical control
A tanker does not sail simply because a government declares the lane open. The owner must accept the risk, the insurer must provide cover, the bank must finance the cargo, the crew must agree and destination ports must accept the ship. Iran can influence every decision by demonstrating that it can identify and strike selected vessels. The resulting delays and premiums create a hidden economic barrier.
Selective coercion is more flexible than total closure
A full blockade would unite many countries against Iran and obstruct Iran's own trade. Selective pressure allows Tehran to reward coordinated or politically friendly traffic while imposing costs on others. It can also deny responsibility or describe incidents as safety enforcement. This ambiguity complicates military retaliation and gives mediators room to negotiate.
The expanded operational-zone claim matters
Iran reportedly broadened its definition of the Hormuz security area from the narrow strait toward Jask, Siri Island and parts of the Gulf of Oman. The claim lacks broad international acceptance, but it expands the area where Tehran may justify surveillance or enforcement. Operational behaviour can change shipping patterns even when the legal argument is rejected.
Electronic interference creates cheap disruption
Navigation depends on GPS, AIS and reliable communications. Jamming or spoofing can produce false positions, encourage ships to switch off tracking or make it harder to distinguish a deliberate attack from an accident. Electronic interference is comparatively inexpensive, difficult to attribute quickly and dangerous in congested lanes used by large vessels with limited manoeuvrability.
Why military strikes cannot eliminate the problem
The United States can destroy known radars, boats and launchers, but dispersed teams can use commercial data, mobile equipment and covert networks. Mines can remain after the platform that laid them is destroyed. The only durable reduction in risk combines deterrence with inspection, demining, hotlines, route publication and a trusted incident-investigation system.
Frequently asked questions
Is selective passage legal?
Political discrimination against neutral commercial shipping is difficult to reconcile with accepted navigation rules. Temporary safety routing can be lawful if it is necessary, transparent and non-discriminatory.
Why do ships sometimes switch off AIS?
Crews may reduce tracking to avoid targeting, but dark sailing also increases collision, compliance and attribution risks.
Could one mine close the strait?
One incident could cause major delays and a temporary traffic halt, but sustained closure would depend on continuing threat perceptions and clearance capacity.
Primary sources and reporting
[4] Reuters, "Hormuz shipping risk raised to severe after tankers hit, reviving U.S.-Iran tensions," 7 July 2026.
[20] International Energy Agency, "Strait of Hormuz," updated February 2026.
[48] Reuters, "Iran now defines Strait of Hormuz as far larger zone, IRGC officer says," 12 May 2026.
[49] United Nations, United Nations Convention on the Law of the Sea, Part III.
[50] Chatham House, analysis of the Strait of Hormuz, shipping and law, 13 April 2026.
[51] Reuters, "Four oil and gas tankers turn back from Hormuz after vessel attacks," 8 July 2026.
Yasir Rai