Iran war: What is the Strait of Hormuz and why does it matter?
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Why the Strait of Hormuz matters so much in the Iran war
5 days ago
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Gavin Butler,
Toby Mann,
Patrick Jacksonand
BBC Persian
Getty Images
When the US and Israel began strikes on Iran on 28 February 2026, Tehran retaliated not only against its two adversaries and their interests in the Gulf, but also by closing the Strait of Hormuz and sending shockwaves through the global economy.
It is one of the world's busiest oil shipping channels, providing passage for about 20% of the world's oil and liquefied natural gas (LNG).
Global fuel prices have soared since then - and been volatile depending on agreements to halt hostilities to allow talks to end the conflict, which have often been broken.
What and where is the Strait of Hormuz?
Bounded to the north by Iran and to the south by Oman and the United Arab Emirates (UAE), the corridor - only about 50km (31 miles) wide at its entrance and exit, and about 33km wide at its narrowest point - connects the Gulf with the Arabian Sea.
The strait is deep enough for the world's biggest crude oil tankers, and is used by major Middle Eastern oil and LNG producers, as well as their customers.
In 2025, about 20 million barrels of oil and oil products passed through the Strait of Hormuz per day, according to estimates from the US Energy Information Administration (EIA). That is nearly $600bn (£447bn) worth of energy trade per year.
The oil comes not only from Iran but other Gulf states such as Iraq, Kuwait, Qatar, Saudi Arabia and the UAE.
About 20% of global LNG is also shipped through the strait, mostly from Qatar. In 2024, it exported about 9.3 billion cubic feet per day (Bcf/d) of LNG through the strait, and the UAE about 0.7 Bcf/d, according to the US government.
LNG is gas turned into liquid - taking up 600 times less space for transport - before being turned back into gas at its destination to be used for heating, cooking and power.
Hormuz is also a crucial route for exports of fertiliser from the Middle East, where natural gas is used heavily in the production process. About one-third of the world's fertiliser trade normally passes through the strait.
The strait is also a vital channel for imports to the Middle East, including food, medicines and technological supplies.
What was the impact of closing the strait and how did Iran effectively block it?
About 3,000 ships usually sail through the strait each month but this dramatically decreased during recent hostilities, with Iran threatening to attack tankers and other ships.
United Nations rules allow countries to exercise control of territorial seas up to 12 nautical miles (13.8 miles) from their coastline.
At the narrowest point, the Strait of Hormuz and its shipping lanes lie entirely within Iran and Oman's territorial waters.
Iranian drones, missiles, fast attack boats and potentially mines presented a serious challenge to boats seeking to travel through the waterway.
"You can be attacked, and you can't get insurance or it is extremely expensive," Arne Lohmann Rasmussen, chief analyst at Global Risk Management, a provider of energy market insights, told CBS News, the BBC's US partner.
Gulf countries, including Iran, rely heavily on energy exports for their income.
Disruption in the strait has also hit Asia hard, with China alone estimated to buy around 90% of the oil that Iran exports to the global market.
In Asia, the fuel crisis continues to impact daily life. Governments ordered employees to work from home, cut the working week, declared national holidays and closed universities early in order to conserve their supplies.
In Africa, South Sudan and Mauritius both announced measures restricting electricity consumption.
In Europe, Slovenia became the first EU member state to implement fuel rationing.
Reuters
About 20% of global oil and gas flows through the Strait of Hormuz
How did the US try to reopen the strait?
The US has not deployed any warships to the strait, confining its military response to air attacks on Iran, including its navy.
It has bombed Iranian anti-ship cruise missile sites along the strait.
Trump previously called for other countries, including both US allies and China, to help secure Hormuz by sending warships, but his request was met with little enthusiasm. He then said the US did not actually need their help.
The US has imposed a naval blockade of Iranian ports to choke off trade with Iran - a measure intermittently enacted when talks appear to flounder and the two sides exchange fire.
The US military has previously been used to re-establish the flow of maritime traffic through the strait.
In the late 1980s, during the eight-year Iran-Iraq war, strikes on oil facilities escalated into a "tanker war" that saw both countries attacking neutral ships to exert economic pressure.
Kuwaiti tankers carrying Iraqi oil were especially vulnerable. Eventually, American warships began escorting them through the Gulf in what became one of the largest naval surface warfare operations since World War Two, according to the US Naval Institute.
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Did ships get through before the ceasefire?
For decades, vessels have been given free passage through the strait.
Before the conflict began, an average of 138 ships crossed through the strait each day, according to the Joint Maritime Information Center (JMIC), a multinational maritime group including the US.
Since 28 February, this fell to just a handful of ships per day.
Iran has stated repeatedly that it will allow "non-hostile vessels" to pass through, provided they co-ordinate with "the competent Iranian authorities".
It has also said traffic arrangements will not be the same as before - going so far as to threaten to impose a fee on each vessel.
Can energy exporters avoid Hormuz?
The persistent threat of closure has, over the years, prompted oil-exporting countries in the Gulf region to develop overland routes.
Saudi Arabia operates the 1,200km-long East–West Crude Oil Pipeline, capable of transporting up to five million barrels of crude oil per day, according to the US government.
In the past, it has also temporarily repurposed a natural gas pipeline to carry crude oil.
The UAE has connected its inland oilfields to the port of Fujairah on the Gulf of Oman via a pipeline with a daily capacity of at least 1.5 million barrels.
Oil could be diverted along the alternate infrastructure to bypass Hormuz but Reuters reports that would lead to a drop in supply of 8-10 million barrels per day.
In addition, oil loading at Fujairah has been disrupted by drone attacks.
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