Twenty percent of the world's oil passes through a body of water that, at its narrowest, is twenty-one miles wide. Ships use two lanes, each two miles across. Iran sits on the north shore. Oman and the UAE sit on the south. Every threat to close it over the past fifty years has eventually not happened — until, in early 2026, it more or less did. This is the full story of the strait: where the name comes from, how its legal status became so contested, every time someone tried to shut it down, and what the 2026 crisis actually looked like from the outside.
Draw a line between the Persian Gulf and the Gulf of Oman. That line is the Strait of Hormuz. At its narrowest point it is twenty-one miles wide, though the shipping lanes themselves — two miles each, inbound and outbound, separated by a two-mile median — are considerably tighter than that. Iran is on the north shore. The southern shore is shared between Oman's Musandam Peninsula and a sliver of the United Arab Emirates. Through those twenty-one miles, in any given year, passes roughly twenty percent of the world's oil supply and twenty percent of its liquefied natural gas. Saudi Arabia's exports. Kuwait's exports. Iraq's exports. Qatar's. The UAE's. All of them go through this one passage because there is no other way out of the Persian Gulf by sea. There are pipelines that bypass it — a few, with limited capacity — but they handle maybe three million barrels a day against the fifteen to twenty million that normally move through the strait. For LNG there is no bypass at all. This makes the Strait of Hormuz the most important twenty-one miles of water on earth. It also makes it a permanent crisis waiting to happen, because one of the countries with a shore on it has been in varying degrees of conflict with the United States and its allies for almost fifty years, and that country has, on more than one occasion, loaded mines onto boats.
The Strait of Hormuz connects the Persian Gulf to the Gulf of Oman — and through its narrow shipping lanes passes roughly one-fifth of the world's entire oil supply, with no viable sea-route alternative.
Where the Name Comes From — There Is More Than One Theory
The name Hormuz has at least four competing explanations and the honest answer is that nobody is certain which one is right. The most commonly cited Persian etymology connects it to Hormoz — the Middle Persian name for Ahura Mazda, the supreme deity of Zoroastrianism. The strait named after a god. Another theory says it comes from a local Persian phrase meaning place of dates, which is considerably more agricultural but not implausible given that date palms grow along these coasts. A third theory attaches the name to Ifra Hormizd, the mother of the Sasanian king Shapur II, who reigned in the fourth century CE. And a fourth possibility traces it to the Greek word hormos, meaning cove or bay, which would make it a Greek geographical term that passed into Persian use during the Hellenistic period. The Kingdom of Ormus — or Hormuz — sat on an island in the strait for several centuries and controlled the trading routes through it. The Portuguese arrived in 1507 and made the kingdom a vassal, which began the first of the strait's periods of being controlled by a foreign naval power. The Portuguese maintained a presence through the eighteenth century, eventually provoking conflict with the English, who arrived in the seventeenth century with their own commercial interests and their own idea of who should control the approaches to the Persian Gulf. A first-century CE mariner's guide called the Periplus of the Erythraean Sea describes the opening of the Persian Gulf — pearl diving, a passage six hundred stadia wide, a market town near the Euphrates — without giving the strait a name at all. The geography was already important enough to document. The name came later.
Who Actually Owns the Shipping Lanes — and Why It Is Complicated
Ships moving through the strait follow a traffic separation scheme: inbound in one lane, outbound in the other, two miles each, two-mile median between them. The lanes sit in Omani territorial waters. To traverse the full length of the strait, ships also pass through Iranian territorial waters. The legal situation this creates has been contested for decades. In 1959, Iran expanded its territorial sea to twelve nautical miles. Oman did the same in 1972. The combined effect was that by 1972, the strait's waters were entirely within the territorial claims of the two countries — there was no strip of international water in between. Whether ships had a legal right of passage through those territorial waters, and under what conditions, immediately became a matter of dispute. Under the UN Convention on the Law of the Sea — UNCLOS — ships have a right of transit passage through international straits used for navigation. Iran has not ratified UNCLOS. The United States has also not ratified it. Both countries nonetheless cite it when convenient and ignore it when not. Iran maintains that foreign warships need permission to transit through its territorial waters. The United States does not recognize that requirement and has never complied with it. The standoff is decades old and has never been resolved, which means that every U.S. Navy ship that goes through the strait is, in Iranian legal theory, doing so illegally, and both sides know it and neither side formally acknowledges it in the normal course of events.
What Passes Through It — the Numbers Are Worth Sitting With
In 2018, twenty-one million barrels of oil per day passed through the Strait of Hormuz. By 2023 to 2025, the figure was running around eighteen to twenty million barrels daily, representing roughly a fifth of global oil consumption. The math on disruption is not abstract: if shipping through the strait stopped for an extended period, Japan, India, South Korea, and China would face oil supply crises, not supply inconveniences. These are countries that import most of their energy. China gets roughly ninety percent of its energy imports through the strait. Beyond oil, twenty percent of the world's LNG passed through in recent years — Qatar is one of the world's largest LNG exporters, and Qatar's only exit to the sea goes through the strait. Fertilizers too: the Persian Gulf accounts for thirty to thirty-five percent of global urea exports and up to thirty percent of internationally traded fertilizers. A prolonged closure would affect not just fuel costs but food production. There is also a black market economy in the strait that functions in parallel with the official one. Small high-speed boats move between the Omani port of Khasab and the Iranian coast — a crossing of about fifty kilometers at the strait's narrowest. Electronics, appliances, cigarettes, and luxury cars move from the UAE through Oman and across to Iran, evading sanctions. Livestock moves the other way. Drugs and undocumented migrants move from Iran toward Oman. Omani authorities in Khasab mostly look the other way because the smuggling economy is a significant income source for an otherwise isolated region. Iranian customs officials estimate the trade costs Iran tens of thousands of jobs and billions in customs revenue annually.
An average of fourteen or more oil tankers per day pass through the Strait of Hormuz — carrying crude oil, LNG, and petroleum products to Asia, Europe, and global markets with no viable alternative sea route.
The Tanker War and Operation Praying Mantis
The first time the strait became a serious military flashpoint in the modern era was during the Iran-Iraq War in the 1980s. Iraq started attacking Iranian oil infrastructure in 1984 — the Kharg Island terminal, tankers loading Iranian crude — with a specific strategic logic. Saddam Hussein wanted Iran to retaliate by closing the strait entirely, which would bring American intervention. Iran did not close the strait. It attacked Iraqi shipping instead, keeping the lane open while the tanker war expanded to involve vessels from multiple nations. By 1988 the United States was directly involved. On 14 April, USS Samuel B. Roberts hit an Iranian mine and nearly sank. Four days later, the U.S. Navy launched Operation Praying Mantis — strikes on Iranian oil platforms and naval vessels in Iranian territorial waters. It was the largest American naval surface battle since World War II. Iran lost two oil platforms, a frigate, a gunboat, and several smaller craft. The same summer, on 3 July 1988, USS Vincennes shot down Iran Air Flight 655 over the strait. All 290 people aboard died. The Navy cruiser had misidentified the Airbus A300 passenger jet as a military aircraft. The United States eventually paid $61.8 million in compensation to the families of the victims but never formally apologized. The incident remains a reference point in Iranian national memory.
The Threats to Close It — Every Cycle Since 2008
Threats to close the strait have followed a pattern since 2008. Iran threatens. Oil prices tick up. The U.S. Navy issues a statement. Analysts say Iran cannot actually close it, or not for long. Nothing happens. In 2008, naval standoffs between Iranian speedboats and U.S. warships in the strait produced a round of statements in which the commander of Iran's Revolutionary Guard said Iran would seal the strait if attacked, the U.S. regional naval commander said that would be an act of war, and both sides essentially acknowledged that the other was not going anywhere. Dozens of U.S. and allied warships eventually gathered in the area for exercises. In late 2011 and early 2012, the pattern repeated with more intensity. An Iranian vice president threatened to cut oil flow through the strait if sanctions cut Iranian exports. The Iranian navy ran exercises in the strait. A flotilla of three American aircraft carriers, British destroyers, and a French frigate assembled in the Persian Gulf and Arabian Sea. An Iranian general said the U.S. carrier had already left because of Iranian naval exercises and should not come back. The U.S. Navy said it would continue operations as normal. Oil futures rose four percent on some of the more alarming statements. In 2018 and 2019, the pattern came around again after the U.S. withdrew from the nuclear deal and reimposed sanctions. Iran test-fired an anti-ship missile over the strait. Iranian forces boarded and seized a British-flagged tanker — described as a reciprocal action for the British seizure of an Iranian tanker in Gibraltar. In June 2019, two oil tankers were struck by explosions; the U.S. blamed Iran, Iran denied it. In each of these cycles, the strait stayed open.