What is the Strait of Hormuz and why does it matter for oil?

The Strait of Hormuz is a narrow sea passage between Oman and Iran that connects the Persian Gulf with the Gulf of Oman and the Arabian Sea. It matters because the Gulf's major exporters ship most of their oil and liquefied natural gas (LNG) through it, and there are few other routes. When ships cannot move through it normally, the effect spreads quickly to fuel and gas prices everywhere.

Key Points

• The strait is the only sea passage from the Gulf to the Indian Ocean, according to the Strauss Center at the University of Texas.
• The IEA says an average of 20 million barrels per day of crude oil and oil products moved through the strait in 2025, with around 25% of the world's seaborne oil trade transiting it.
• Roughly 19% of global LNG trade also passes through, according to the IEA, much of it from Qatar.
• Pipelines can carry only part of the oil around the strait, so closure cannot simply be rerouted away.
• The 2026 disruption shows the mechanism at work: the IEA describes it as the largest supply disruption in the history of the global oil market.

Understanding the Strait of Hormuz

The strait is a geographic bottleneck. The EIA defines chokepoints as narrow channels along widely used global sea routes that are critical to global energy security. Hormuz fits that description because of what sits behind it. The IEA says it is the primary export route for oil produced by Saudi Arabia, the UAE, Kuwait, Qatar, Iraq, Bahrain and Iran.

The passage is narrow but deep. The EIA says it is deep enough and wide enough to handle the world's largest crude oil tankers. At its narrowest point it is 21 miles wide, but the shipping lane in each direction is only two miles wide, separated by a two-mile buffer zone. The Strauss Center adds that much more of the strait than the formal shipping lanes is deep enough for the very largest oil tankers. A barrier to traffic would therefore have to cross the full width of the strait, not just the narrow band of the lanes.

Hormuz is not the world's busiest oil chokepoint by volume. The EIA says the Strait of Malacca, with an estimated 23.2 million barrels per day in the first half of 2025, is the largest chokepoint in the world in terms of oil transit volume. What sets Hormuz apart is the lack of alternatives. The EIA states that most volumes that transit it have no other way out of the region.

How It Works

Several things combine to turn a local disruption into a global price event.

1. Geography concentrates the flow. Exporters around the Gulf load tankers inside the strait's approaches, and those ships must pass through two narrow lanes. The lanes have been governed since 1968 by an IMO-mandated traffic separation scheme, according to the Washington Institute. The scheme has inbound and outbound lanes, each two nautical miles wide, separated by a two-mile zone.
2. Bypass routes are limited. The IEA says only Saudi Arabia and the UAE have operational crude pipelines that could re-route flows around the strait, with an estimated 3.5 to 5.5 mb/d of available capacity. The EIA's own estimate for the Saudi East-West pipeline and the UAE's Abu Dhabi pipeline together is about 4.7 million b/d. The IEA notes that Aramco reported in March 2025 that it had raised the Saudi pipeline's capacity to 7 mb/d, though sustainable flows have not been tested at that level. The EIA's conclusion is that alternatives could move only a portion of the oil volumes out of the strait.
3. Spare capacity is trapped too. The IEA says a prolonged disruption could make unavailable most of the world's spare production capacity, which is mostly held by Saudi Arabia. The usual cushion against a supply loss sits behind the same chokepoint.
4. Delays and costs ripple outward. The EIA says the inability of oil to transit a major chokepoint, even temporarily, can create substantial supply delays and raise shipping costs, potentially increasing world energy prices. Buyers compete for cargoes from elsewhere, and prices rise globally, not only in the regions that import from the Gulf.

Why It Matters

Hormuz matters most to Asia, but its effects are global. The EIA estimates that 89% of the crude oil and condensate moving through the strait went to Asian markets in the first half of 2025. It says China, India, Japan and South Korea together accounted for 74% of all Hormuz crude and condensate flows. Oil is a globally traded commodity, though, so a shortage in Asia raises prices for every buyer.

Oil is not the only exposure. The EIA reports that 11.4 Bcf/d of LNG transited the strait in the first half of 2025, over 20% of global LNG trade, primarily from Qatar. The IEA says about 93% of Qatar's and 96% of the UAE's LNG exports pass through it. The IEA also notes that more than 30% of global urea trade and about 20% of ammonia and phosphate trade move through the strait, along with a large part of seaborne sulphur trade. A closure therefore reaches fertilizer and food supply chains as well as fuel.

The 2026 Disruption

The IEA says the war in the region that began on 28 February has impeded energy trade flows through the strait, creating the largest supply disruption in the history of the global oil market. Its Executive Director has said the combined impacts amount to "the greatest threat to global energy security in history."

The IEA's March 2026 Oil Market Report, published 12 March 2026, says flows of crude and oil products through the strait plunged from around 20 mb/d before the war to a trickle. It adds that Gulf countries cut total oil production by at least 10 mb/d. The same report series says Brent futures traded within a whisker of $120/bbl after the United States and Israel launched joint air strikes on Iran on 28 February.

Governments responded with stockpiles. On 11 March, IEA member countries unanimously agreed to make 400 million barrels of emergency oil stocks available, which the IEA describes as the largest-ever release coordinated by the agency. Each of its 32 member countries must hold stocks equal to at least 90 days of net oil imports, a requirement that goes back to the agency's founding in 1974. The IEA calls the release a stop-gap measure and says the ultimate impact depends crucially on how long shipping through the strait is disrupted.

Related Terms

• Chokepoint: A narrow channel on a major sea route where a disruption can hold up a large share of global energy trade.
• Traffic separation scheme: A system of designated inbound and outbound shipping lanes. The Washington Institute says the entire Hormuz scheme lies within Omani territorial waters.
• Transit passage: The legal right under UNCLOS of ships and aircraft to pass through qualifying international straits continuously and expeditiously.
• Emergency oil stocks: Government-mandated reserves that IEA members can release collectively when supply is cut.
• Spare production capacity: Oil output that producers can bring online quickly in a shortage, much of it held in the Gulf.

Frequently Asked Questions

Who controls the Strait of Hormuz under international law?

No single country controls passage. The Washington Institute says that under UNCLOS the strait qualifies as an international strait governed by "transit passage," legally defined as non-suspendible, non-discriminatory, and free of state authorization or tolls for the mere act of transit. UNCLOS Article 38 says all ships and aircraft enjoy the right of transit passage, which shall not be impeded. Article 44 says bordering states shall not hamper it and that there shall be no suspension of it. Article 41 lets bordering states designate sea lanes and traffic separation schemes, with proposals referred to the competent international organization, and ships must respect them.

Why is the legal position disputed?

The Washington Institute says Iran is not a party to UNCLOS and has long rejected the transit passage regime in favor of an expansive "innocent passage" interpretation. Oman is a party to UNCLOS. Washington Institute analysts Noam Raydan and Farzin Nadimi wrote on Aug 5, 2026 that Iranian authorities have effectively established a new navigational order. They said the internationally recognized traffic separation scheme has been rendered effectively unnavigable for many operators.

Can pipelines replace the strait?

Only in part. The EIA and IEA both point to Saudi and Emirati pipelines as the sole real bypass, and the EIA says they could move only a portion of the volumes. Qatar's LNG has no comparable pipeline route out, and the IEA says about 93% of its LNG exports transit the strait.

How reliable is the shipping data for 2026?

Less reliable than usual. The EIA explains that much of its chokepoint data rests on ship Automatic Identification System (AIS) signals, which may be incomplete if the signal is manipulated or turned off. The EIA states that since the end of February 2026, "AIS signal data for ships transiting the Strait of Hormuz have become especially unreliable," and that 2026 Hormuz tanker-tracking data are being revised frequently.

Last updated: October 5, 2026. For the latest energy news and analysis, visit stakeandpaper.com.