Why Did Iran Close the Strait of Hormuz? The Reasons Explained

Iran shut the strait to strike back at the countries attacking it and to raise the cost of the war for everyone who depends on Gulf oil. On February 28 the Revolutionary Guards told ships the waterway was closed and unsafe because of the US and Israeli attacks. On March 2 Ebrahim Jabari, a senior adviser to the Guards’ commander, said the Guards and the regular navy would “set those ships ablaze” if anyone tried to pass. Iranian leaders had threatened for decades to block the strait if the country was attacked. In 2026 they did it.

The first target was Iran’s enemies, not all shipping. On March 5 the Guards said the strait was closed to ships from the United States, Israel, Europe and their Western allies, arguing that in wartime Iran had the right to control passage. Later in March, Iran told the International Maritime Organization, the UN shipping agency, that “non-hostile” vessels could cross in coordination with Iranian authorities, and some ships from countries Tehran counted as friendly were let through.

Because no other pressure point hurts Iran’s opponents and the world economy at the same time. Mojtaba Khamenei, in his first statement as supreme leader on March 12, 2026, said that “the lever of closing the Strait of Hormuz must definitely be used,” and the Guards announced the same day that they would keep it shut on his orders.

The numbers explain the choice. In 2024, before the war, about 20 million barrels of oil a day passed through the strait, roughly a fifth of world consumption. It is the only sea route out of the Gulf for Saudi Arabia, Iraq, Kuwait, Qatar, the United Arab Emirates and Iran itself, and only Saudi Arabia and the UAE have pipelines that can carry part of their exports around it. Closing it lifts oil prices everywhere and puts pressure on every government that buys Gulf energy. Why Is the Strait of Hormuz Important? sets out who depends on it.

Iran closed it again each time a truce or a deal broke down, and each time it named a new grievance.

On April 18, a day after Foreign Minister Abbas Araghchi declared the strait “completely open” during a ceasefire in Lebanon, Iran’s Khatam al-Anbiya Central Headquarters said control had “returned to its previous state.” Its spokesman called the US blockade of Iranian ports, enforced since April 13, “piracy” and a breach of the ceasefire.

On June 11, Iran’s military ordered the strait closed to all tankers and commercial ships after US strikes on Bandar Abbas, Qeshm Island and Sirik. The strikes came after a US Apache helicopter was brought down over the strait on June 8.

On June 20, three days after President Donald Trump and President Masoud Pezeshkian signed the Islamabad Memorandum, the same headquarters shut the strait again. It accused Washington of failing to carry out the memorandum’s first clause and Israel of breaking the ceasefire in southern Lebanon.

On July 11, the Guards’ navy declared the strait closed “until further notice” and until American “interventions” in the region end, after firing a warning shot at a ship it said had used an unapproved route. The United States resumed its blockade on July 14, and the strait has stayed closed in practice since then.

Iran now says the strait stays shut until the United States meets its demands. On October 4 the speaker of parliament, Mohammad Bagher Ghalibaf, said it would not reopen until seven conditions were met, and on October 7 Mohammadreza Naqdi, an adviser to the Guards’ commander, said the closure would last “until Iran’s legitimate demands are met.” The demands center on ending the blockade, lifting sanctions, releasing frozen assets and ending the war on all fronts, Lebanon included. Iran Turns Its Hormuz Offer Into Seven Conditions covers the list. On November 1 Araghchi said the strait could reopen within two days of Washington acting, and on November 8 he wrote that the offer stands.

Washington has not accepted those terms. Trump said on November 10 that the blockade stays for now, and Secretary of State Marco Rubio told G7 foreign ministers the same day that the blockade and sanctions were working well enough that major combat was not needed. Iran also insists that ships use a route it approves and coordinate with its forces. For Saudi Arabia and the other Gulf exporters, a reopening on those terms, with Iran deciding who passes and at what price, would not be a reopening at all. What Is the U.S. Blockade of Iran? explains the other half of the standoff.

No. Iran threatened to close it many times, including in 2008 and again in late 2011 and 2012 over Western sanctions on its oil, but before 2026 it had never shut the strait for any length of time. Even during the Tanker War of the 1980s, when Iran and Iraq attacked hundreds of merchant ships, traffic kept moving, and US warships escorted reflagged Kuwaiti tankers through the Gulf in 1987 and 1988. The 2026 closure is the first sustained one since the strait became the world’s main oil corridor.

Iran does not have to block the water; it only has to make the passage too dangerous for owners and insurers. The strait is about 21 nautical miles wide at its narrowest point, and its shipping lanes run through Omani waters within easy reach of Iran’s coast, which forms the strait’s northern shore, and its islands, Qeshm among them. From there the Guards can hit ships with fast boats, drones and anti-ship missiles, and they can stop and seize vessels.

Mines are the disputed part. Since October, the Guards and Iran’s regular navy have claimed a string of tankers hit by mines, none of them named and none confirmed by any maritime authority, while US Central Command says the main routes are clear of Iranian mines. How Many Naval Mines Does Iran Have? looks at that arsenal.