Strait of Hormuz

Strait of Hormuz, only sea channel linking the oil-rich Persian Gulf (west) with the Gulf of Oman and the Arabian Sea (southeast). In March 2026, amid the 2026 Iran war, threats and attacks by Iran on ships passing through the strait led to a more than 95 percent drop in traffic, leading to the biggest disruption ever in the global oil supply and a surge in the price of other critical commodities.

More than 20 percent of global oil and liquefied natural gas exports passes through the strait, which serves as the primary route for petroleum exported from Iran, Iraq, Kuwait, Qatar, and the United Arab Emirates (although the United Arab Emirates has the capability to divert most of its exports through its Fujairah emirate on the Gulf of Oman). The exports are geographically focused—about four-fifths go to importing countries in Asia, especially China, India, Japan, and South Korea—but the volume of the supply has profound impact on pricing worldwide due to the low elasticity of prices for petroleum products. Along with the Strait of Malacca that connects the Indian Ocean to the Pacific Ocean, the Strait of Hormuz is one of the most vital oil chokepoints in the global economy.

Geography and shipping

The strait is 35 to 60 miles (55 to 95 km) wide and separates Iran (north) from Oman’s Musandam exclave on the Arabian Peninsula (south). Bandar Abbas, an Iranian port of both economic and military importance, lies on its northern coastline, near which are the Iranian islands of Qeshm (Qishm), Hormuz, Hengām (Henjām), and Lārak. The United Arab Emirates is also located near the strait, about 40 to 50 miles (65 to 80 km) to the strait’s narrowest point on either side of the Musandam Peninsula. Although based some distance from the strait, the U.S. Navy’s Fifth Fleet has been based in Bahrain since 1995 and plays a role in guaranteeing safe passage in the strait.

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Water and its Varying Forms

Oil tankers pass through the strait in inbound and outbound shipping lanes that are 2 miles (3 km) in width and separated by a two-mile buffer zone. The shipping lanes lie mostly in Omani territorial waters, and somewhat in Iranian territorial waters, but they are governed by international maritime law and according to the United Nations Convention on the Law of the Sea (UNCLOS). Iran controls the strait north of the shipping lanes and Oman controls the strait to the south. Although Iran has the capacity to disrupt shipping, most of the strait is deep enough (200 to 330 feet [60 to 100 meters]) to handle oil tankers and it has long been assumed that Iran does not have the ability to block the entire width of the strait for a prolonged period of time. Nonetheless, during the 2026 Iran war, the threat of confrontation alone proved enough to divert more than 90 percent of commercial traffic and demonstrated Iran’s asymmetric leverage over the strait’s traffic.

Incidents in the oil chokepoint

In 1984, during the Iran-Iraq War, the feuding Persian Gulf countries began attacking each other’s oil-tanker shipping and Iran also attacked tankers heading to and from Kuwait and other Gulf states. The so-called Tanker War, which included strikes on more than 100 oil tankers, prompted the involvement of the United States and several western European nations to ensure the safe passage of oil tankers in and out of the Gulf. In the 21st century Iranian and U.S. naval forces have engaged in several standoffs in the strait.

After U.S. strikes on nuclear facilities in Iran during the 12-Day War in June 2025, the Iranian parliament, dominated by hard-liners since elections in 2020, authorized Iran’s armed forces to close the strait. Although an attempt to close the strait did not take place—it required the approval of Iran’s Supreme National Security Council and the conflict ended only two days later—the parliament’s move triggered fears of oil price hikes globally and the heightening tensions led some tankers to reverse course to avoid the strait.

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Shortly after the outbreak of the 2026 Iran war, Iran made it a key part of its retaliatory strategy to choke off traffic through the strait. Traffic plummeted merely by the outbreak of conflict, but it decreased to a trickle as Iranian forces began attacking vessels and, according to U.S. officials, laying submarine (naval) mines. Some of the few tankers that successfully passed through the strait originated from Iran. Within days the price of oil on the global market surged, as did the price of natural gas, fertilizers, critical metals like aluminum, and other commodities whose supply chains rely on access to the Persian Gulf. Parts of Asia east of the strait experienced immediate fuel shortages, leading to extraordinary measures to conserve energy. When the United States and Iran agreed to a temporary ceasefire in early April, Iran reportedly agreed to allow safe passage to ships through the strait during the cessation. But as Israel continued its bombardment of Lebanon, an arena that Iran considered to be part of the ceasefire agreement despite denials from the United States, Iran continued to restrict access to the strait. After an initial round of direct negotiations between the United States and Iran failed to produce an agreement, the U.S. Navy began a blockade of the strait on April 13 to prevent the passage of any ships transiting through Iranian ports. An attempt by U.S. forces to facilitate transit through the strait took place on May 4 and May 5, but only two ships passed under U.S. guidance before the operation was paused.

On May 5 Iran announced the creation of the Persian Gulf Strait Authority (PGSA), an Iranian agency that attempted to establish protocols for transit through the strait and implement a toll regime. In a memorandum of understanding with the United States reached in June, both parties agreed that the U.S. Navy would lift its blockade and Iran “will make arrangements using its best efforts for the safe passage of commercial vessels,” including negotiating with Oman and the other Gulf states “to define the future administration and maritime services in the Strait of Hormuz.” As the blockade was lifted and traffic through the strait slowly gained momentum, Iran warned ships that it would guarantee safe passage only under the routes and protocols established by the PGSA. The threats were met with objections from the United States, which insisted that the memorandum did not allow Iran to impose any restrictions on transit through the strait. On July 6 and 7 Iran attacked three ships as they passed through an alternate route along the Omani coast. The move prompted the United States to renew hostilities and reimpose its blockade.