Iran Controls Strait of Hormuz Shipping

What's happened

As of mid-March 2026, Iran exerts selective control over the Strait of Hormuz, a vital maritime chokepoint through which 20% of global oil passes daily. Since the US-Israel strikes on February 28, multiple attacks on vessels have disrupted traffic, causing tanker flows to collapse by over 90%. Iran allows limited passage to allies via negotiated safe corridors, while many ships transit with tracking systems off. The US has deployed Marines and threatens military action if Iran mines the strait.

What's behind the headline?

Strategic Leverage Through Selective Passage

Iran's shift from an open international waterway to a system of "selective passage" through the Strait of Hormuz represents a calculated strategy to exert maximum pressure on global energy markets without triggering a full blockade. By allowing only certain vessels—primarily those from allied or neutral countries—to transit via negotiated safe corridors, Iran maintains leverage while avoiding the severe international backlash a total closure would provoke.

Impact on Global Energy and Shipping

The collapse of tanker traffic by over 90% in March and the accumulation of roughly 1,100 ships waiting in Gulf waters highlight the severe disruption to global oil supply chains. Gulf producers are rerouting exports through pipelines bypassing the strait, but these alternatives cannot fully compensate for the lost maritime capacity, contributing to elevated and volatile oil prices.

Covert Operations and Risk Management

The widespread use of "dark transit" tactics—ships switching off AIS tracking systems—reflects efforts by shipping companies to evade targeting and sanctions. This shadow fleet activity underscores the high-risk environment and the lengths operators will go to maintain oil flows.

Military and Diplomatic Dimensions

The US deployment of Marines and threats of military action if Iran mines the strait signal Washington's intent to deter further escalation. However, Iran's resilience and control over the strait complicate efforts to restore free navigation. Diplomatic negotiations with countries like India and Turkey to secure passage for their vessels indicate Iran's willingness to use the strait as a bargaining chip.

Forecast

The strait will remain a focal point of geopolitical tension, with Iran leveraging its control to influence global energy markets and international diplomacy. Unless a diplomatic breakthrough occurs, disruptions and elevated oil prices will persist, with the risk of further military escalation looming if Iran intensifies attacks or imposes a full blockade.

How we got here

The conflict escalated after US and Israeli strikes on Iran on February 28, 2026, including the assassination of Iran's supreme leader. Iran's Revolutionary Guard Corps declared full control over the Strait of Hormuz, threatening to block shipping. The strait is a critical route for global oil and liquefied natural gas exports, making its closure a major threat to energy markets and global trade.

Our analysis

The New Arab reports that Iran has implemented a "selective passage" system, effectively deciding which vessels may transit the Strait of Hormuz, with tanker traffic collapsing by over 90% in March and about 1,100 ships waiting in Gulf waters. The New Arab cites Iranian Foreign Minister Abbas Araghchi stating the strait is "open" but "closed only to our enemies," highlighting Iran's strategic control. The Independent provides detailed tracking of vessels like the Pakistan-flagged Karachi (Lorax), which transited with AIS signals on, suggesting Iran's direct guidance and selective permission. Freight analyst Matthew Wright notes that Iran is managing oil flows to friendly Asian partners, but warns this selective approach cannot be broadly expanded without undermining Iran's leverage on oil prices. The New York Times outlines the US military response, including deploying Marines and considering naval escorts for merchant ships, while noting Iran's resilience to aerial bombardment and artillery strikes. It also discusses the historical context of mine warfare in the strait and current US efforts to clear mines. Reuters and The Independent report on Iran's deployment of mines and attacks on vessels, with the UK Maritime Trade Operations confirming multiple attacks since the conflict began. President Trump has warned Iran against mining the strait, threatening unprecedented military consequences. Together, these sources illustrate a complex picture of Iran's strategic use of the Strait of Hormuz as a bargaining tool amid ongoing conflict, with significant implications for global energy security and geopolitical stability.

Go deeper

• How is Iran controlling shipping through the Strait of Hormuz?
• What impact does the disruption in the Strait of Hormuz have on global oil prices?
• What is the US military's response to the situation in the Strait of Hormuz?

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