Iran's temporary closure of the Strait of Hormuz brings an ultra-sensitive sea corridor for about a fifth of the world's oil to the forefront of Middle East tensions.
Any closure of the strait between Iran and the Gulf states, which is less than 35km wide at its narrowest point, risks adding economic turmoil to the region's simmering conflicts.
Unlike in the Red Sea, where Houthi attacks have pushed many ships on to an alternative route around the tip of Africa, trade in the Strait of Hormuz has remained relatively unaffected by recent conflicts.
About 11 per cent of all global trade and a third of seaborne oil trade flow through the strait, according to UN figures. Prices spiked in the tanker market in June 2025, when Iran and Israel fought a 12-day air war that culminated in a US intervention and an Iranian strike on Qatar.
Iran has several times threatened to close the waterway during times of high tension, which would also affect the natural gas trade. Attacks occurred during the Tanker War of the 1980s, when Iran and Iraq tried to stop each others’ exports. A US warship shot down an Iranian airliner over the strait in 1988, killing 290.
The restrictions on Tuesday came as US and Iranian diplomats held indirect talks in Geneva aimed at averting another war.
“There is no alternative route to the Strait of Hormuz,” Jakob Larsen, chief safety and security officer at shipping firm Bimco, told The National earlier this week.
Naval forces belonging to Iran's Islamic Revolutionary Guard Corps began drills near the strait on Monday. The exercise is known as Smart Control of the Hormuz Strait.
The live-fire drills are being supervised by IRGC commander-in-chief Mohammad Pakpour, state media said. It said the exercises aim to test the navy's readiness and prepare for “possible security and military threats” in the strait.
Around one-fifth of the world’s crude, or around 20 million barrels of oil, transits through the Strait of Hormuz, which is shared by Iran and Oman. Capacity on the route from China to the UAE – which passes through the strait – has been rising since November 2025.
Oil produced in Iran, Saudi Arabia and other Gulf countries passes through the route. Saudi Arabia, the world's largest exporter of crude, moves more hydrocarbons through the strait than any other Gulf nation.
