Home › Water › Straits & Canals
The Strait of Hormuz
The narrow outlet of the Persian Gulf, through which about a fifth of the world's oil passed in 2025
No stretch of water matters more to the price of a barrel of oil. The Strait of Hormuz is the only sea exit from the Persian Gulf, which Arab states call the Arabian Gulf, and the tankers of Saudi Arabia, Iraq, Kuwait, the United Arab Emirates, Qatar, and Iran all have to pass through it. In 2025 the U.S. Energy Information Administration put the flow at about 21 million barrels of oil a day, roughly a fifth of world supply, plus most of Qatar's liquefied natural gas. In 2026 the strait showed what a closure looks like: when war broke out with Iran, traffic collapsed and the shock rippled from fuel pumps in Manila to factories in Europe.
The strait curves for about 167 kilometers between Iran to the north and the Musandam Peninsula, an exclave of Oman, to the south, linking the Gulf with the Gulf of Oman and the Arabian Sea. At its narrowest it is about 39 kilometers wide, but the usable route is far tighter: a traffic separation scheme of two lanes, each just 3.7 kilometers wide with a buffer between them, running through Omani territorial waters off Musandam's cliffs. The Iranian shore holds the port of Bandar Abbas and a chain of islands, among them Qeshm, Hormuz, Larak, and Hengam. Just to the west lie Abu Musa and the Greater and Lesser Tunbs, which Iran has held since 1971 and which the United Arab Emirates claims.
Hormuz was a trading kingdom long before oil, held by the Portuguese from 1515 until an Anglo-Persian force expelled them in 1622. Its modern weight came with the Gulf oil fields, and with every crisis since the Tanker War of the 1980s. Iran has never ratified the UN Convention on the Law of the Sea and disputes the right of transit passage. After U.S. and Israeli strikes on Iran began on February 28, 2026, Iran declared the strait closed to ships it deemed unfriendly, and more than 90 attacks on merchant ships followed. A ceasefire came in April, the United States imposed a naval blockade of Iranian ports, and a June memorandum briefly eased traffic. In October 2026 Iran said the strait would stay closed until its conditions were met, and transits remained a fraction of prewar levels.