Overview
Iran has executed a long-threatened move to close the Strait of Hormuz, cutting off a corridor that typically conveys roughly 20% of the world's oil and liquefied natural gas. The action follows a series of strikes by the United States and Israel and has precipitated a sharp drop in vessel transits. United Nations data indicate traffic through the strait has fallen by about 97% since the conflict expanded on February 28. The closure has generated immediate concern in global energy markets and among maritime security planners.
Why the closure occurred now
The idea of blocking the strait is not new. A senior commander in Iran's Islamic Revolutionary Guard Corps once said closing the passage would be "easier than drinking a glass of water," and the same threat has surfaced repeatedly during earlier tensions over sanctions and nuclear talks as well as in response to strikes in recent years. Analysts historically treated such a move as a last resort because it could provoke long-term strategic shifts among adversaries and invite retaliation against Iran's own energy infrastructure.
Those calculations have shifted since the attack that began on February 28 with the killing of Iran's supreme leader. Iranian officials now describe the current conflict as existential, and control of strategy has increasingly rested with the Guards. In that environment, Tehran opted to act on a previously stated threat and effectively sealed the strait.
What the strait carries and what is at stake
The Strait of Hormuz is the narrow sea passage between Iran and Oman that connects the Gulf to the Gulf of Oman. It is the only maritime exit for major oil and gas producers in the region, including Kuwait, Iran, Iraq, Qatar and the United Arab Emirates. The strait normally handles about a fifth of global oil and liquefied natural gas supplies.
The immediate market reaction included a rise in oil prices to their highest levels since 2022 as traders priced in supply risk. The United Nations has warned that a sustained period of elevated oil prices could prompt broad economic pain, including a renewed cost-of-living crisis similar to effects seen after other major supply disruptions. There are also commodity secondary effects: analytics firm Kpler estimates about 33% of the world's fertilizers, including sulphur and ammonia, transit the strait. Interruptions to those shipments risk a fertilizer shortage and potential stress on global food security.
Why the strait is difficult to secure
Several physical and operational features make securing the Strait of Hormuz a complex task. The main shipping lanes narrow to about two nautical miles in places. Vessels must perform a turn opposite Iranian-held islands and a mountainous coastline that offers natural cover for forces ashore. Those geographic constraints compress movement and make ships more vulnerable to localized threats.
Iran's conventional navy has been largely degraded over time, but the Islamic Revolutionary Guard Corps retains a range of asymmetric options. Those include fast attack craft, mini submarines, sea mines and small surface vehicles like jetskis loaded with explosives, according to Tom Sharpe, a retired Royal Navy commander. Tehran also has a significant drone production capacity; the Centre for Information Resilience, a non-profit research group, estimates Iran can produce on the order of 10,000 drones per month.
Escorting tankers through the strait on a limited basis is technically possible in the short term. Sharpe noted that escorting three or four ships a day could be achieved using seven or eight destroyers providing air cover, contingent on a reduced risk from sub-surface threats such as mini submarines. Sustaining that level of protection for weeks or months, however, would demand far more resources. Even if major Iranian missile, drone and mine capabilities were neutralized, maritime and coastal vulnerabilities would remain because of the possibility of suicide operations, Adel Bakawan, Director of the European Institute for Middle East and North African Studies, said.
Kevin Rowlands, Editor of the RUSI Journal at the Royal United Services Institute, observed that if the conflict endures for weeks, some form of escort coalition is likely to be organized. He emphasized that the world has a material need for the flow of Gulf oil and that planning is underway to implement protective measures, even if those measures are resource-intensive.
What states have said they will do
U.S. leadership has offered to protect shipping through the strait. President Donald Trump stated on March 3 that the United States would provide protection for oil tankers and that he had directed the U.S. Development Finance Corporation to supply insurance and guarantees for shipping firms. Despite that promise, attacks have already occurred and very little commercial shipping is passing through the strait.
France and other European countries have signaled an interest in maritime protection. French President Emmanuel Macron said several European states, India and other Asian countries were preparing a joint mission to safeguard shipping but added that such an operation could only take place once the conflict had ended. France has also deployed roughly a dozen naval vessels, which include an aircraft carrier strike group, to the eastern Mediterranean, the Red Sea and potentially the Strait of Hormuz.
British officials have engaged in consultations with German and Italian leaders about options to support commercial shipping. At the Pentagon, General Caine indicated that a range of options is under consideration but did not provide operational details.
Lessons from recent chokepoint disruptions
Yemen's Houthi movement offers a recent example of how a relatively less-equipped actor can disrupt maritime trade. Despite having a far smaller arsenal than Iran, the Houthis managed to curtail most traffic through the Red Sea and the Bab al-Mandab Strait on the route to the Suez Canal for more than two years, even in the face of U.S. and EU-led protection missions. As a result, many shipping companies rerouted vessels around the Cape of Good Hope, lengthening voyages. Maersk, the Danish shipping company, had indicated a phased return to the Suez route from January, reflecting the uneven restoration of secure transit.
An EU-led effort has shown greater success against piracy off Somalia, but those operations confronted adversaries with far fewer capabilities than those available to Iran's Revolutionary Guards.
Are there viable alternatives to the strait?
Regional producers have pursued non-maritime options to bypass the strait, notably pipelines. The United Arab Emirates and Saudi Arabia have advanced projects to move cargo by land, but those pipelines are not fully operational at scale. Past attacks on east-west pipeline infrastructure have illustrated the vulnerability of overland alternatives; for example, a 2019 Houthi strike on a Saudi east-west pipeline demonstrated that such routes are not immune to disruption.
Market and economic implications
Immediate market effects include elevated oil prices and heightened concern about fertilizer supply chains, both of which carry broader economic risks. Prolonged disruption could raise the prospect of more systemic inflationary pressures and tighter conditions for sectors reliant on petrochemicals and agricultural inputs. The scale and duration of such effects will depend on how quickly multinational navies can organize sustainable escorts, the resilience of regional pipeline alternatives, and whether Iran moderates its posture.
Conclusion
The closure of the Strait of Hormuz underscores how geography and asymmetric maritime capabilities combine to give a state like Iran significant leverage over global energy flows. While short-term military options exist to escort limited numbers of vessels, sustaining those operations at the scale necessary to restore normal trade will be resource-intensive. Governments and commercial actors are evaluating options, but the combination of constrained waterways, asymmetric threats and the strategic significance of the strait means uncertainty will persist so long as the conflict continues.