Strait of Hormuz
One-fifth of the world's oil passes through a channel narrower than the length of Manhattan — and the country that borders it has repeatedly threatened to shut it down.
The short version
- The Strait of Hormuz is a narrow waterway between Iran and Oman connecting the Persian Gulf to the open ocean. In 2024, approximately 20 million barrels of oil per day — roughly 20% of global petroleum consumption and 27% of all seaborne oil trade — transited the strait, making it the single most critical energy chokepoint on Earth.
- At its narrowest point the strait is just 22 nautical miles wide, with two shipping lanes of two miles each separated by a two-mile buffer zone, all falling within Iranian and Omani territorial waters — giving Iran physical proximity to every tanker that passes through.
- Iran has threatened to close the strait numerous times over the past four decades and possesses the naval assets — fast attack craft, sea mines, anti-ship missiles — to disrupt traffic, but has never fully closed it, in part because Iran's own economy depends on oil exports that must transit the same waterway.
- Pipeline alternatives capable of bypassing the strait can reroute only about 2.6 million barrels per day — roughly 13% of the oil that flows through it — meaning that a sustained closure would create a supply gap that no existing infrastructure could fill.
What it is
The Strait of Hormuz is the narrow sea passage between Iran to the north and Oman (and the tip of the United Arab Emirates) to the south, connecting the Persian Gulf — where roughly half the world's proven oil reserves sit beneath the surrounding nations — to the Gulf of Oman and the open Arabian Sea beyond. The strait is about 96 miles long and just 22 nautical miles wide at its narrowest point. Two inbound and two outbound shipping lanes, each two miles wide and separated by a two-mile buffer, carry the vast majority of crude oil exported by Saudi Arabia, Iraq, Kuwait, the UAE, and Qatar. In 2024, oil flows through the strait averaged 20 million barrels per day, equivalent to roughly 20% of the world's total petroleum liquids consumption. An additional one-fifth of global liquefied natural gas (LNG) trade — primarily from Qatar, the world's second-largest LNG exporter — also passes through these waters. No other chokepoint on the planet handles a comparable volume of energy.
The strait's strategic significance is inseparable from its geography. Both shipping lanes fall within the territorial waters of Iran and Oman, meaning that every commercial vessel transiting the strait does so under the legal jurisdiction of one or both coastal states. Under the United Nations Convention on the Law of the Sea (UNCLOS), the strait qualifies for the regime of 'transit passage,' which guarantees freedom of navigation for international shipping — but enforcement of that right in a contested military environment is a different matter entirely. Iran maintains two parallel naval forces with responsibility for these waters: the regular navy (IRIN) operates beyond the Gulf, while the Islamic Revolutionary Guard Corps Navy (IRGCN) controls the Persian Gulf itself, with both sharing jurisdiction over the strait. The IRGCN operates large numbers of fast attack craft, small submarines, and shore-based anti-ship cruise missiles positioned along Iran's southern coastline.
The history of military confrontation in these waters is extensive. During the Iran-Iraq War (1980–1988), both belligerents attacked commercial shipping in what became known as the Tanker War: 411 ships were attacked over seven years, 239 of them oil tankers. Iraq struck first, targeting tankers loading at Iran's Kharg Island terminal beginning in 1981, hoping to provoke Iran into closing the strait and thereby drawing in the United States. Iran retaliated against Gulf Arab shipping and laid mines in the strait, leading to Operation Earnest Will — the U.S. Navy's escort of re-flagged Kuwaiti tankers through the Gulf from 1987 to 1988 — and culminating in Operation Praying Mantis in April 1988, the largest U.S. naval surface engagement since World War II. Even at the height of the Tanker War, less than 2% of transiting ships were actually disrupted, and the strait was never fully closed — but insurance premiums spiked, shipping patterns shifted, and the precedent for military confrontation in these waters was permanently established.
Since the 1980s, tensions have flared repeatedly. In 2011–2012, Iran threatened to close the strait in response to Western sanctions over its nuclear program. In 2019, Iran seized a British-flagged tanker in the strait and was accused of attacking several commercial vessels with limpet mines, prompting the formation of international naval coalitions to protect shipping. In June 2025, following U.S. and Israeli strikes on Iranian nuclear facilities, U.S. intelligence detected Iranian military forces loading naval mines onto vessels in the Persian Gulf — a preliminary step toward blockade that was ultimately not carried out. Then in February 2026, Iran partially closed the strait during Revolutionary Guard military exercises while U.S.-Iran talks proceeded in Geneva, and following U.S.-Israeli strikes on Iran on February 28, 2026, Iran's IRGC reportedly moved to close the waterway entirely — representing an unprecedented escalation in the strait's long history as a flashpoint.
Why it matters
The strait's importance is ultimately mathematical. Twenty million barrels per day cannot be rerouted. Saudi Arabia operates the East-West Pipeline, which can move up to 5 million barrels per day to Red Sea terminals bypassing the strait, and the UAE's Habshan-Fujairah pipeline connects Abu Dhabi's oil fields to a terminal on the Arabian Sea. But combined, these alternatives can handle only about 2.6 million barrels per day of actual reroutable capacity — barely 13% of what flows through the strait daily. The remaining 17-plus million barrels per day have no alternative route. A sustained closure would remove roughly one-fifth of global oil supply from the market with no mechanism to replace it, a scenario that energy analysts and the Congressional Research Service have assessed would trigger an immediate global recession.
The price signal alone can cause damage before a single barrel is physically disrupted. Oil markets operate on expectations: the risk premium built into crude prices reflects traders' assessments of supply disruption probability. Brent crude reached approximately $73 per barrel in late February 2026 amid escalating tensions — and analysts estimated that an extended closure could push prices 15–20% higher within days. For importing nations, the exposure is asymmetric. An estimated 84% of crude oil transiting the strait in 2024 went to Asian markets. China, the world's largest crude importer, purchases more than 80% of Iran's shipped oil; India receives over 1 million barrels per day through the strait and holds only 9.5 million barrels in strategic reserves — roughly a week's supply. Japan and South Korea depend heavily on Saudi and Kuwaiti crude that has no alternative export path. The United States, by contrast, imported only about 0.5 million barrels per day from Persian Gulf countries through the strait in 2024, its lowest level in nearly 40 years — but in a globally integrated oil market, a price spike anywhere is a price spike everywhere.
Iran's relationship to the strait embodies a strategic paradox that has restrained escalation for decades but may not restrain it indefinitely. Iran possesses the military capability to disrupt shipping — its fast attack craft, unmanned systems, anti-ship missiles, and mine-laying capacity are purpose-built for asymmetric warfare in confined waters. But Iran's own economy depends on oil and gas exports that must transit the same waterway. Closing the strait would devastate Iran's revenue alongside everyone else's, which is why Iran has historically treated the threat of closure as a deterrent rather than an operational plan. The calculus changes, however, when Iran perceives an existential threat — as it did following the nuclear facility strikes in 2025 and the broader military strikes in February 2026. Under those conditions, the economic self-harm of closure may be weighed against regime survival, and the restraint that geography has imposed may give way to the logic of escalation.
The deeper structural vulnerability is that the global economy has known about this single point of failure for half a century and has not meaningfully reduced its dependence on it. Despite the development of pipeline alternatives, the growth of U.S. shale production, the buildout of strategic petroleum reserves, and decades of rhetoric about energy independence, the arithmetic has barely moved: the strait carried about 17 million barrels per day in the early 2010s and carries 20 million today. The volume has grown because Asian demand has grown, and because the Gulf states that sit upstream of the strait hold the world's cheapest-to-produce reserves and largest spare capacity. No combination of alternative suppliers, renewable energy deployment, or demand reduction has changed the basic fact that one-fifth of the world's oil supply funnels through a channel where a single state actor with a grievance and a navy can hold the global economy hostage. The Strait of Hormuz is not just an energy chokepoint — it is a structural vulnerability in the architecture of the world economy that reprices itself every time a missile is fired within range of its shipping lanes.
Sources & Further Reading
- Amid Regional Conflict, the Strait of Hormuz Remains Critical Oil Chokepoint
- Iran Conflict and the Strait of Hormuz: Oil and Gas Market Impacts (R45281)
- Strait of Hormuz
- The Strait of Hormuz Is the World's Most Important Oil Transit Chokepoint
- Strait of Hormuz Factsheet
- World Oil Transit Chokepoints