Shipping traffic through the Strait of Hormuz, a major maritime choke point for world energy trade, has been largely blocked by Iran since 28February 2026, when the United States and Israel launched an air war against Iran. In retaliation, the Iranian Revolutionary Guard Corps (IRGC) issued warnings forbidding passage through the strait, boarded and attacked merchant ships, and laid sea mines in the strait. From 13 April to 29 May 2026, the US simultaneously blockaded Iranian ports. Until the war's start, about 25% of the world's seaborne oil trade and 20% of the world's liquefied natural gas (LNG) passed through the strait.
Soon after the start of the conflict, the number of tankers trafficking the strait dropped near zero. On 27 March, the IRGC announced that the strait was closed to any vessel going "to and from" the ports of the US, Israel, and their allies. The International Maritime Organization reported on 21 April that about 20,000 mariners and 2,000 ships were stranded in the Persian Gulf due to the closure. Amid fears of prolonged supply shortages, oil prices rose faster than during any other conflict in recent history; Brent crude oil prices surpassed US$100 per barrel on 8March for the first time in four years, rising to US$126per barrel at their peak. The largest-ever monthly increase in oil prices occurred in March 2026. The closure of the strait became the largest disruption to world energy supply since the 1970s energy crisis as well as the largest in the history of the world oil market. Other commodity markets to suffer supply disruption and price increases due to the crisis include aluminum, fertilizer, and helium.
In late March and early April, US president Donald Trump repeatedly threatened to destroy Iran's infrastructure if it did not reopen the strait. On 8 April a temporary ceasefire between Iran and the US was agreed and was to involve the reopening of the strait. However, following the failure of the Islamabad Talks, the US Navy itself began to blockade Iranian ports from 13 April."U.S. to Blockade Ships Entering or Exiting Iranian Ports", press release, 12 April 2026, U. S. Central Command. Accessed 14 April 2026. The situation was described by The Guardian as a "dual blockade", with the US Navy blockading Iran and Iran blockading the Gulf. On 17 April, Iran announced that due to an Israel–Lebanon ceasefire agreement, it would allow commercial shipping, but the US continued its blockade of Iran, and Iran reimposed restrictions. On 4 May, Trump launched Operation Project Freedom, a US Navy mission to escort merchant ships out of the Gulf. The Iranian military warned that this would be a ceasefire violation, and on 6 May, Trump paused Project Freedom because of "great progress" toward a possible agreement.
On 17 June, Trump and Iranian president Masoud Pezeshkian signed a memorandum of understanding to end the war and the blockades of the strait. On 19 June, Trump announced a renewed ceasefire between Israel and Hezbollah, facilitated by the US, Qatar, and Iran. However, Israel continued strikes in southern Lebanon, and the following day, Iran said that it closed the strait again, citing the Israeli actions as a violation of the agreement, a claim denied by the US military. On 27 June, the Joint Maritime Information Center (JMIC) overseen by the US Navy announced a widened route through the Strait of Hormuz near Oman, allowing increased naval traffic in both directions and indicating a challenge to Iran's control over the waterway. On 8 July, the interim truce agreement between the US and Iran broke down after Iran struck multiple commercial ships in the Strait of Hormuz. On 25 August, US officials confirmed Trump's claim that the US Navy cleared mines from the Strait of Hormuz Traffic Separation Scheme, adding that over recent months, underwater drones identified over 100 suspected mines and private contractors dealt with them. Trump stated that the US will destroy Iranian vessels laying additional mines in the Strait of Hormuz.
Background Global oil trade
The strait is wide at its narrowest point, forming a seaway passage between Iran and Oman. Its two unidirectional sea lanes facilitate the transit of around 20 million barrels of oil per day, representing roughly 20% of global seaborne oil trade, primarily from Saudi Arabia, the United Arab Emirates, Iraq, and Qatar. In 2024, an estimated 84% of crude oil and condensate shipments through the strait were destined for Asian markets, with China receiving a third of its oil via the strait, and had about a billion barrels in oil reserve (a few months of supply). Europe gets 12% to 14% of its LNG from Qatar, through the strait.
The Persian Gulf is also a major hub for global fertilizer production and exports. In the 2020s the region has accounted for roughly 30% – 35% of global urea exports and around 20% – 30% of ammonia exports. Overall, up to 30% of internationally traded fertilizers normally transit the Strait of Hormuz.
Geopolitical tensions Tensions between Iran and the United States resulted in the 1988 Operation Praying Mantis, included some European countries in the 2011–2012 Strait of Hormuz dispute, and again in 2019.
Tensions between Iran, the United States, and Israel escalated in the lead-up to 2026, stemming from failed nuclear negotiations in Geneva and a prior 12-day air conflict in 2025. Iran had signaled potential disruptions to the Strait of Hormuz in response to threats, including a temporary partial closure earlier in the month as a warning. From 15 to 20 February, Iran increased its oil export to three times its normal rate and reduced oil storage to reduce risk of disruptions. Saudi Arabia also attempted similar moves. In the days before the strikes, war-risk ship insurance premiums for the strait increased from 0.125% to between 0.2% and 0.4% of the ship insurance value per transit. For very large oil tankers, this is an increase of a quarter of a million dollars.
In briefings held before the February 2026 attacks, the Joint Chiefs of Staff warned President Trump that an attack could prompt Iran to close the strait. Trump acknowledged the warnings, but dismissed the possibility, telling his team that Iran would likely capitulate instead of closing the strait, and if they did, the US military could open it again.
Escalation
On 28 February 2026, the United States and Israel initiated coordinated airstrikes on Iran under Operation Epic Fury, targeting military facilities, nuclear sites, and leadership, resulting in the death of Supreme Leader Ali Khamenei. Iran responded with missile barrages on Israeli cities and US bases in the Gulf, including in the UAE, Qatar, and Bahrain, causing casualties and infrastructure damage. The conflict expanded to Lebanon, where Iran-backed Hezbollah launched rockets into Israel, prompting Israeli counterstrikes.
On 4 March, Iran announced that the Strait of Hormuz, a key waterway for the shipping of oil, LNG, and other products, was "closed", and threatened to attack any ship that attempted to pass it. It would eventually make exceptions for ships from countries it deemed to be "friends" of the republic, as with seven stranded Malaysian ships that it allowed to pass through the strait on 6 April. On 9 March, Iran declared that they would bring more security passage to the countries that expels US and Israel ambassadors. By 9 March, shipping insurance rates for the strait were reported to have increased by four to six times over the previous week, and the US government began to offer help to insurers under the Terrorism Risk Insurance Act, while continuing to warn commercial shipping against the area. The same day, Trump said that Iran's military had been destroyed, that the strait was open, and that the US might seize control of it from Iran to keep it open for commercial activity. On 27 March, he reaffirmed his desire to control the strait and also expressed interest in renaming it either to the "Strait of America" or to the "Strait of Trump", later referencing the latter name in a speech.
Iranian blockade List of ships attacked by Iran
+ # Date Name Flag Type Result Sources1Skylight; 2 crew killed, including captain2MKDVyom; 1 crew killed–Sea LaDonna3Hercules Star4Ocean Electra5–6Stena Imperative7AtheNova8Gold Oak9Pelagia10Libra Trader1112Safeen Prestige13Sonangol Namibe14Mussafah2; 4 crew dead–Prima–LouisP15UnknownN/A16Mayuree Naree; 3 crew killed17One Majesty18Star Gwyneth–Express Rome19Safesea Vishnu20Zefyros21Source Blessing22Gas Al Ahmadiah23Parimal24Halul 6925UnknownN/A26Express Rome27Al Salmi28Aqua 1–MSC Ishyka29Sanmar Herald30CMA CGM Everglade31Mein Schiff 4 and escaped with 5 other cruise ships32MSC Epaminondas (aka Epimonidas) — 8 crew repatriated in June 202633MSC Francesca34Euphoria35UnknownN/A36Barakah37HMM Namu38JV Innovation39CMA CGM San Antonio40Ocean Koi41Safesea Neha42Haji Ali43Hui Chuan44MSC Sariska V45Ever Lovely 46Kiku47Al Rekayyat48Wedyan49Cyprus Prosperity50GFS Galaxy51Stolt Magnesium52Mombasa B53Al Bahyah54Kavomaleas55Acheloos56Kaifan57Gaslog Shanghai58Unknown59Minoan Pioneer60UnknownN/A61Navig8 Messi62Tarif63Al Watan64Minoan Dignity 65Metro Venetian66Al Salam II67Burgan68Sidr69Senegal Prosperity70Hercules Star71New Andros72El Gaia73Trend74Unknown75STI Steadfast76Al Maryah77LR Stephanie78Cape Dao79Al Funtas80Mersin Prosperity81Sinbad82Al Ruwais83Kazimah III84Uhud85Ghana Prosperity86Lipsi87Cameroon Prosperity88Gas Vela 89Maran Gas Mystras90On Peace Footnotes:
Tools for closure Iran's methods of restricting traffic in the strait include:
Attacks from speed boats (500 to 1000+), missiles and drones are the physical way of keeping ships away. Iran has laid mines as a hidden threat which could be anywhere. Satellite spoofing and GNSS jamming makes navigation harder.
These three methods are easy to deploy and difficult to oppose, and prohibitively increase insurance cost, preventing most shipowners from sailing through.
Timeline Within hours of the US and Israeli strikes on 28 February, the IRGC transmitted warnings via VHF radio to vessels in the strait, stating that no ships would be permitted to pass. Iran did not formally declare a blockade, but military and industry sources warned that safety could not be guaranteed, and several ships stayed in port or turned back. The threats led to a partial closure, with ship-tracking data first showing a 70%reduction in traffic.
March On 1March, the oil tanker Skylight was struck by a projectile north of Khasab, Oman, killing two Indian crew members and injuring three others. The rest of its 20crew evacuated. It was sanctioned by the US Department of Treasury for links to the Iranian shadow fleet. The MKDVYOM was struck by a drone boat, sparking a fire and an explosion in its engine room. An Indian sailor was killed, and its 21crew evacuated on the Panama-flagged MVSAND. Another Indian was critically wounded on the LCTAyeh.
On 2March 2026, a senior official in the IRGC officially confirmed that Iran had closed the strait, threatening any ship that attempted to pass the strait. The US-flagged Stena Imperative was struck twice at the port of Bahrain, causing a fire. A port worker was killed and two others hurt in the attack, though the ship's crew were unharmed. The Athe Nova, which has links to Iran, was struck by two drones after attempting to illegally cross, according to the IRGC-linked Tasnim News Agency.
Just after midnight on 2March, no tankers in the strait broadcast automatic identification system signals, indicating low or no traffic, though with unreliable data and satellite navigation device basis. Protection and indemnity insurance, which is critical for shipping, was removed from 5March, making the economic risk too high for ship owners to use the strait. It was declared a high-risk zone, requiring extra pay and the right of refusal for ships' crew. The strait remained legally open, but effectively closed.