Strait of Hormuz

Imagine a narrow waterway, just a sliver of blue on the map, yet it holds the key to a quarter of the world's seaborne oil and a fifth of its liquefied natural gas. This is the Strait of Hormuz, a critical maritime passage connecting the Persian Gulf to the open ocean. Its strategic location makes it a perpetual flashpoint, where global energy security and regional tensions often collide. The Strait of Hormuz is the world's most vital oil chokepoint, with a significant portion of global energy supplies transiting its waters daily. Navigating the Strait involves complex international law and territorial claims by Iran and Oman, leading to ongoing geopolitical tensions. Despite numerous threats and incidents, the Strait has never been fully closed, though alternative pipeline routes are being developed to reduce reliance on this precarious passage.

Source: Wikipedia

AI Summary

Imagine a narrow waterway, just a sliver of blue on the map, yet it holds the key to a quarter of the world's seaborne oil and a fifth of its liquefied natural gas. This is the Strait of Hormuz, a critical maritime passage connecting the Persian Gulf to the open ocean. Its strategic location makes it a perpetual flashpoint, where global energy security and regional tensions often collide.

The World's Most Important Waterway?

Nestled between the Persian Gulf and the Gulf of Oman, the Strait of Hormuz is more than just a body of water—it's a critical maritime artery. It serves as the sole sea passage from the oil-rich Persian Gulf to the vast expanse of the open ocean. This unique position makes it an indispensable conduit for global trade.

To put its importance into perspective, consider this: as of 2023, a staggering 25% of all seaborne oil trade and 20% of the world's liquefied natural gas passes through this narrow strait. This makes it a lynchpin for global energy markets and a focal point for international politics.

A Narrow But Mighty Passage

Geographically, the Strait is a relatively short stretch, about 104 miles (167 km) long. Its width varies dramatically, from a broad 60 miles (97 km) down to a constricted 24 miles (39 km) at its narrowest point. To the north lies the coastline of Iran, while the southern coast is controlled by Oman's Musandam Peninsula, shared in part with the United Arab Emirates.

Whispers of the Past: Etymology

The name 'Hormuz' itself is steeped in history and legend, with several theories vying for its origin. A popular idea connects it to Ahura Mazda, the ancient Zoroastrian god, through the Middle Persian pronunciation. Another suggestion is 'Hur-Muz,' meaning 'Place of Dates,' perhaps referring to the region's historical agricultural bounty.

Greek mariners in the 1st century CE described this opening to the Persian Gulf in texts like the 'Periplus of the Erythraean Sea,' though they didn't give it a specific name. It wasn't until the 10th-17th centuries that the powerful Kingdom of Ormus, a significant trading hub, likely lent its name to the strategic strait.

Navigating the Chokepoint

Given the sheer volume of traffic and the Strait's narrowness, safe passage is paramount. To mitigate the risk of collisions, ships adhere to a strict Traffic Separation Scheme, or TSS. This system designates two distinct, two-mile-wide lanes—one for inbound vessels and one for outbound—separated by a two-mile-wide 'median' buffer zone.

However, navigating these waters isn't just about traffic rules; it's also about international law. Ships transit through the territorial waters of both Iran and Oman. While the United Nations Convention on the Law of the Sea generally allows for 'transit passage,' both nations have, at different times, asserted claims that complicate this, particularly for warships.

Iran, for instance, requires specific permission for foreign warships and nuclear-powered vessels to pass through its territorial waters. Oman, upon ratifying UNCLOS, also declared that prior permission is needed for foreign warships. The United States, however, does not recognize these additional requirements, leading to persistent legal and operational disagreements.

A History of High Stakes and Tensions

The Strait of Hormuz has long been a stage for geopolitical drama, reflecting the volatile dynamics of the region. During the 1980-88 Iran-Iraq War, the 'Tanker War' phase saw both sides attack each other's oil shipping, though Iran notably refrained from closing the Strait entirely, despite threats.

A tragic event occurred in July 1988, when the USS Vincennes, a U.S. Navy guided-missile cruiser, mistakenly shot down an Iran Air commercial airliner over the Strait, killing all 290 people on board. This incident underscores the extreme tension and high stakes involved in military operations within the Strait's confines.

More recently, the Strait has witnessed numerous incidents involving ship seizures and threats from Iran. In 2015, Iranian patrol boats fired shots across the bow of a Marshall Islands-flagged container ship, the Maersk Tigris, forcing it into Iranian waters over a debt dispute. Such actions highlight the risks faced by commercial shipping in the area.

In 2019, tensions flared again with attacks on oil tankers, including the Front Altair and Kokuka Courageous, which the U.S. attributed to Iran. Later that year, Iran seized the British-flagged Stena Impero, describing it as a 'reciprocal action' following the seizure of an Iranian tanker near Gibraltar. These events prompted increased international naval presence.

In a display of its potential to disrupt traffic, U.S. intelligence in 2025 reportedly detected Iran loading naval mines onto vessels in the Persian Gulf. While these mines were not ultimately deployed, the incident sent a clear message about Iran's capability and willingness to escalate tensions around the Strait.

Threats to Close the Strait

Iran has repeatedly threatened to close the Strait of Hormuz, often in response to international sanctions or perceived aggression. These threats are typically met with warnings from the U.S. and its allies, who emphasize their commitment to ensuring the freedom of navigation through this vital waterway.

In 2012, amidst new sanctions, Iran's military chief explicitly warned the U.S. Navy not to return an aircraft carrier to the Persian Gulf, stating Iran would 'take action' if it did. The U.S. responded by affirming its right to operate in international waters, underscoring the impasse over sovereign claims versus international navigation rights.

Closing the Strait, even temporarily, would have catastrophic economic consequences. Analysts predict a surge in oil prices, potentially leading to global inflation and an economic downturn. However, experts also note that such a move would severely harm Iran's own economy, as its oil exports are entirely sea-based.

The Question of Closure

The practical feasibility of Iran completely closing the Strait has been a subject of extensive military analysis and war games. While Iran possesses capabilities like naval mines and fast boats, the U.S. and its allies maintain a strong naval presence specifically to counter such a threat.

A 2002 U.S. war game, Millennium Challenge, controversially simulated a scenario where a simulated 'Iran' successfully blocked the Strait. However, subsequent analyses have questioned the assumptions of these exercises, suggesting any closure would be short-lived due to the overwhelming military capabilities of opposing forces.

Seeking Alternatives: Bypass Routes

Recognizing the inherent risks associated with relying so heavily on the Strait, several Gulf nations have invested in alternative pipeline routes. Saudi Arabia, for instance, reopened the Iraq Pipeline through Saudi Arabia (IPSA), providing an overland route to the Red Sea with a capacity of 1.65 million barrels per day.

The United Arab Emirates also commissioned the Habshan–Fujairah oil pipeline, bypassing the Strait entirely by transporting crude from Abu Dhabi to the Gulf of Oman. This pipeline can move up to 2 million barrels per day, significantly enhancing the UAE's energy security and reducing its dependence on the Strait. These alternatives aim to create resilience in global energy supply chains.

Article

Strait of Hormuz

The Strait showing maritime political boundaries and shipping lanes, (2004)

Strait of Hormuz topographic map showing the Musandam Peninsula of Oman in the south and Iran to the north

The Strait of Hormuz () is a waterway between the Persian Gulf and the Gulf of Oman. On the north coast lies Iran, and on the south coast lies the Musandam Peninsula, shared by the United Arab Emirates and the Musandam Governorate, an exclave of Oman. The strait is about 104 miles (90 nmi; 167 km) long, with a width varying from about 60 mi (52 nmi; 97 km) to 24 mi (21 nmi; 39 km).

It provides the only sea passage from the Persian Gulf to the open ocean and is one of the world's most strategically important choke points. During 2023–2025, 20% of the world's liquefied natural gas (LNG) and 25% of seaborne oil trade passed through the strait annually. It is a major source of petroleum products for Europe and Asia and has been described as "critical" to Europe's energy security. It is also the only maritime route for several Gulf countries including Qatar, Kuwait and Bahrain, and disruption to the strait can cause severe supply shortages.

The strait has traditionally never been closed for extended time during Middle East conflicts (unlike the Straits of Tiran/Bab-el-Mandeb) though Iran occasionally had threatened to close the strait, and preparations to mine it have been undertaken. However, the strait became a major focus of the international community during the 2026 Iran War, resulting in the Strait of Hormuz crisis.

Etymology

Strait of Hormuz

Persian etymology derives "Hormuz" from the Middle Persian pronunciation of the name of the Zoroastrian god هرمز Hormoz (Ahura Mazda). Alternatively, it has been suggested that the name derives from the local Persian word Hur-Mogh هورمغ 'Place of Dates'. A theory claims that the strait of Hormuz may have been named after Ifra Hormizd, the mother of King Shapur II of Persia, who ruled between 309 and 379 AD. Another theory is that it comes from ὅρμος hormos, the Greek word for 'cove, bay'.

The opening to the Persian Gulf was described, but not given a name, in the Periplus of the Erythraean Sea, a 1st-century mariner's guide:

At the upper end of these Calaei islands is a range of mountains called Calon, and there follows not far beyond, the mouth of the Persian Gulf, where there is much diving for the pearl-mussel. To the left of the straits are great mountains called Asabon and to the right there rises in full view another round and high mountain called Semiramis; between them the passage across the strait is about six hundred stadia; beyond which that very great and broad sea, the Persian Gulf, reaches far into the interior. At the upper end of this gulf, there is a market-town designated by law called Apologus, situated near Charaex Spasini and the River Euphrates.

In the 10th–17th centuries AD, the Kingdom of Ormus was located here.

First western military dominance in the strait. Portuguese presence in the Persian Gulf (1507–1750)

From the 15th century onward, from a strategic point of view, the geography of the strait maintained and expanded its importance with the arrival of foreign powers such as Portugal, which maintained its presence between the 16th and 18th centuries, also provoking disputes with other emerging powers such as England when it arrived in the region in the 17th century.

Navigation

Strait of Hormuz

To reduce the risk of collision, ships moving through the strait follow a traffic separation scheme (TSS): inbound ships use one lane, outbound ships another, each lane being two miles wide. The lanes are separated by a two-mile-wide "median".

To traverse the strait, ships pass through the territorial waters of Iran and Oman. Although Iran has not ratified the UNCLOS convention, most countries, including the U.S. which also has not ratifed it, claim the right of passage as codified in the convention.

In 1959, Iran altered the legal status of the strait by expanding its territorial sea to 12 nmi (22 km) and declaring it would recognize only transit by innocent passage through the newly expanded area. In 1972, Oman also expanded its territorial sea to 12 nmi (22 km) by decree. Thus, by 1972, the Strait of Hormuz was completely "closed" by the combined territorial waters of Iran and Oman. In 1971, Iran took over the Greater and Lesser Tunbs islands west of Hormuz against Arab wishes, thereby extending control of the navigation channels.

During the 1970s, neither Iran nor Oman attempted to impede the passage of warships, but in the 1980s, both countries asserted claims that were different from customary (old) law. Upon ratifying UNCLOS in 1989, Oman submitted declarations confirming its 1981 royal decree that only innocent passage is permitted through its territorial sea. The declarations further asserted that prior permission was required before foreign warships could pass through Omani territorial waters.

Upon signing the convention in 1982, Iran entered a declaration stating "that only states parties to the Law of the Sea Convention shall be entitled to benefit from the contractual rights created therein", including "the right of transit passage through straits used for international navigation". In 1993, Iran enacted a comprehensive law on maritime areas, provisions of which conflict with UNCLOS provisions, including a requirement that warships, submarines, and nuclear-powered ships obtain permission before exercising innocent passage through Iran's territorial waters. The U.S. does not recognize any of the claims by Oman and Iran and has contested each of them.

Oil trade flow

Strait of Hormuz

Oil trade through the strait by origin and destination, 2014–2018

During 2023–2025, 20% of the world's liquefied natural gas and 25% of seaborne oil trade passed through the Strait, illustrating its important location for trade.

According to the U.S. Energy Information Administration, in 2011, an average of 14 tankers per day passed out of the Persian Gulf through the strait carrying 17 million barrels (2,700,000 m3) of crude oil. More than 85% of these crude oil exports went to Asian markets on a daily basis, with Japan, India, South Korea and China the largest destinations. In 2018, 21 million barrels a day passed through the strait, worth $1.2 billion at 2019 prices.

If shipping through the Strait of Hormuz were significantly disrupted for an extended period, it could lead to a major oil supply crisis for major Asian importers such as India and China.

The Persian Gulf is also a major hub for global fertilizer production and exports. Countries such as the Islamic Republic of Iran, Qatar, Saudi Arabia, and Oman are among the world’s leading exporters of nitrogen fertilizers, including urea and ammonia. In the 2020s the region has accounted for roughly 30–35 percent of global urea exports and around 20% - 30% of ammonia exports. Overall, up to 30% of internationally traded fertilizers normally transit the Strait of Hormuz.

Events

Strait of Hormuz

The strait as seen from an airliner at 35,000 feet (10,700 m). Musandam is in the foreground.

Tanker War

The Tanker War phase of the Iran–Iraq War started when Iraq attacked the oil terminal and oil tankers at Iran's Kharg Island in early 1984. Saddam Hussein's aim in attacking Iranian shipping was, among other things, to provoke the Iranians to retaliate with extreme measures, such as closing the Strait of Hormuz to all maritime traffic, thereby bringing American intervention. Iran limited the retaliatory attacks to Iraqi shipping, leaving the strait open.

Operation Praying Mantis

Operation Praying Mantis was an attack on 18 April 1988 by the United States Armed Forces within Iranian territorial waters in retaliation for the Iranian naval mining of international waters in the Persian Gulf during the Iran–Iraq War and the subsequent damage to an American warship. The U.S. Navy attacked with several groups of surface warships, plus aircraft from the aircraft carrier USS Enterprise, and her cruiser escort, USS Truxtun. The attack began with coordinated strikes by two surface groups.

Downing of Iran Air 655

On 3 July 1988, 290 people were killed when an Iran Air Airbus A300 was shot down over the strait by the United States Navy guided missile cruiser USS Vincennes (CG-49) when it was wrongly identified as a jet fighter.

Collisions

In January 2007, the nuclear submarine USS Newport News struck MV Mogamigawa, a 300,000-ton Japanese-flagged crude tanker, south of the strait. There were no injuries, and no oil leaked. On 20 March 2009, United States Navy Los Angeles-class submarine USS Hartford collided with the San Antonio-class amphibious transport dock USS New Orleans in the strait. The collision ruptured a fuel tank aboard New Orleans, spilling 95 cubic metres (25,000 US gal) of marine diesel fuel.

Iranian navy problems

In May 2020, Iran launched missiles at one of their own ships in a friendly fire accident, killing 19 sailors. On 2 June 2021, the IRIS Kharg, a modified Ol-class replenishment oiler of the Iran Navy, sank in the Strait of Hormuz after catching fire. It was the navy's largest vessel.

Iranian ship seizures

On 28 April 2015, IRGCN patrol boats contacted the Marshall Islands–flagged container ship Maersk Tigris, which was westbound through the strait, and directed the ship to proceed further into Iranian territorial waters, according to a spokesman for the U.S. Defense Department. When the ship's master declined, one of the Iranian craft fired shots across the bridge of Maersk Tigris. The captain complied and proceeded into Iranian waters near Larak Island. The U.S. Navy sent aircraft and a destroyer, USS Farragut, to monitor the situation. Maersk says it agreed to pay an Iranian company $163,000 after an Iranian court ruling over a dispute about 10 container boxes transported to Dubai in 2005. An appeal court raised the fine to $3.6 million.

On 4 January 2021, the Tasnim News Agency reported that a South Korea–flagged oil vessel headed from Saudi Arabia to the United Arab Emirates was seized for allegedly causing pollution violations. The ship was said to be carrying roughly 7,000 tons of ethanol. South Korea refused to comment on the accusation of causing oil pollution in the Strait of Hormuz. The ship, Hankuk Chemi, was headed to the UAE port Fujairah after loading oil from Jubail, Saudi Arabia on 2 January 2021, as per ship-tracking data gathered by Bloomberg.

In April 2024, the Iranian Navy seized MSC Aries, a Portuguese-flagged container ship sailing through the Gulf of Oman off the UAE coast of the Emirati port city of Fujairah, then steered the container ship through the strait, with 25 personnel on board, claiming that it had violated maritime laws. The crew of 25 included 17 Indian nationals, Filipinos, Pakistanis, a Russian, and an Estonian.

Iranian preparations to mine the strait

As of 2019, the U.S. Defense Intelligence Agency estimated that Iran possessed over 5,000 naval mines capable of rapid deployment via high-speed boats. In June 2025, it was reported that U.S. intelligence detected, possibly through satellite imagery or human informants, that Iranian military forces loaded naval mines onto vessels in the Persian Gulf, an act which was interpreted as a preliminary step to blockading the strait. The mines were ultimately not deployed, though their presence raised alarms in Washington about Tehran's intent to escalate the conflict. It is unclear whether the mines were later removed.

2008

Naval stand-offs between Iranian speedboats and U.S. warships in the strait occurred in December 2007 and January 2008. U.S. officials accused Iran of harassing and provoking their naval vessels, but Iran denied the allegations. On 14 January, U.S. Navy officials appeared to contradict the Pentagon version of the 16 January event, in which the Pentagon had reported that U.S. vessels had almost fired on approaching Iranian boats. The Navy's regional commander, Vice Admiral Kevin Cosgriff, said the Iranians had "neither anti-ship missiles nor torpedoes" and he "wouldn't characterize the posture of the US 5th Fleet as afraid of these small boats".

On 29 June, the commander of Iran's Revolutionary Guard, Mohammad Ali Jafari, said that if either Israel or the U.S. attacked Iran, it would seal off the strait to wreak havoc in the oil markets. Cosgriff warned that such Iranian action would be considered an act of war, and the U.S. would not allow Iran to hold hostage a third of the world's oil supply. On 8 July, Ali Shirazi, a mid-level clerical aide to Iran's Supreme Leader Ayatollah Ali Khamenei, was quoted telling the Revolutionary Guards, "The Zionist regime is pressuring White House officials to attack Iran. If they commit such a stupidity, Tel Aviv and U.S. shipping in the Persian Gulf will be Iran's first targets and they will be burned."

In the last week of July, in Operation Brimstone, dozens of U.S., and naval ships from other countries, came to undertake joint exercises for possible military activity in the shallow waters off the coast of Iran. By 11 August, more than 40 U.S. and allied ships were en route to the strait.

2011–2012

On 27 December 2011, Iranian vice president Mohammad Reza Rahimi threatened to cut off oil supply from the strait should economic sanctions limit, or cut off, Iranian oil exports. A U.S. Fifth Fleet spokeswoman said the Fleet was "always ready to counter malevolent actions", whilst Admiral Habibollah Sayyari of the Islamic Republic of Iran Navy claimed cutting off oil shipments would be "easy". Despite an initial 2% rise in oil prices, markets ultimately did not react significantly to Iran's threat, with oil analyst Thorbjoern Bak Jensen concluding "they cannot stop the flow for a longer period due to the amount of U.S. hardware in the area".

The guided-missile destroyer USS Porter transits the Strait of Hormuz in May 2012. Porter is deployed to the U.S. 5th Fleet.

On 3 January 2012, Iran threatened to take action if the U.S. Navy moved an aircraft carrier back into the Persian Gulf. Iranian Army chief Ataollah Salehi said the U.S. had moved a carrier out of the Persian Gulf because of Iran's naval exercises, and Iran would take action if the ship returned. "Iran will not repeat its warning ... the enemy's carrier has been moved to the Gulf of Oman because of our drill. I recommend and emphasize to the American carrier not to return to the Persian Gulf", he said.

U.S. Navy spokesman Commander Bill Speaks responded that deployment of U.S. military assets would continue as has been the custom stating: "The U.S. Navy operates under international maritime conventions to maintain a constant state of high vigilance in order to ensure the continued, safe flow of maritime traffic in waterways critical to global commerce." While earlier statements from Iran had little effect on oil markets, coupled with new sanctions, later comments drove crude futures higher, up over 4%. Pressure on prices reflected a combination of uncertainty driven further by China's response – reducing oil January 2012 purchases from Iran by 50% compared to 2011.

By January 2012, U.S.-led sanctions began to show economic effects, as the Iranian currency lost 12% of its value. Further pressure on Iranian currency was added by France's Foreign Minister Alain Juppé who was quoted as calling for more "strict sanctions" and urged EU countries to follow the U.S. in freezing Iranian central bank assets and imposing an embargo on oil exports.

On 9 January 2012, Iran's Defense Minister Ahmad Vahidi denied that Iran had ever claimed it would close the strait, saying that "Iran is the most important provider of security in the Strait ... if one threatens the security of the Persian Gulf, then all are threatened." Iran's Foreign Ministry confirmed on 16 January it had received a letter from the U.S.; authorities were considering whether to reply, although the contents of the letter were not divulged. The U.S. had previously announced its intention to warn Iran that closing the strait is a "red line" that would provoke an American response.

General Martin Dempsey, the chairman of the Joint Chiefs of Staff, said the U.S. would "take action and re-open the Strait", which could be accomplished only by military means, including minesweepers, warship escorts and potentially airstrikes. U.S. defense secretary Leon Panetta told troops that the U.S. would not tolerate Iran closing the strait. Nevertheless, Iran continued to discuss the impact of shutting the strait on oil markets, saying any disruption of supply would cause a shock "no country" could manage.

A U.S. Navy convoy in the strait in July 2016

By 23 January, a flotilla had been established by countries opposing Iran's threats to close the strait. These ships operated in the Persian Gulf and Arabian Sea off the coast of Iran. The flotilla included three American aircraft carriers, three destroyers, seven British warships, including the destroyer HMS Daring and four Type 23 frigates, and the French frigate La Motte-Picquet. On 24 January, tensions rose further after the European Union imposed sanctions on Iranian oil. A member of Iran's parliament said, "If any disruption happens regarding the sale of Iranian oil, the Strait ... will definitely be closed".

2018–2019

In July 2018, Iran again made threats to close the strait, citing looming American sanctions after the U.S. withdrew from the JCPOA deal. In August, Iran test-fired a ballistic missile. According to the officials, the anti-ship Fateh-110 Mod 3 flew over 100 miles on a flight path over the strait to a test range in the Iranian desert. "It was shore-to-shore", said a U.S. official.

On 22 April 2019, the U.S. ended the oil waivers, which had allowed some of Iran's customers to import Iranian oil, without risking financial penalties as part of U.S. economic sanctions. Al Jazeera quoted Major-General Mohammad Bagheri of the Iranian Armed Forces, stating "We are not after closing the Strait of Hormuz but if the hostility of the enemies increases, we will be able to do so... If our oil does not pass, the oil of others shall not pass the Strait of Hormuz either".

2019 attacks on oil tankers

Iran has persistently attacked vessels and seized ships amidst political issues. On 13 June 2019, the oil tankers Front Altair and Kokuka Courageous were rocked by explosions shortly before dawn; the crew of the latter reported seeing a flying object strike the ship. They were rescued by the destroyer USS Bainbridge while the crew of the Front Altair were rescued by Iranian ships. U.S. secretary of state Mike Pompeo issued a statement accusing Iran of the attacks, Iran denied this calling it a false-flag attack.

In July 2019, a Stena Bulk Tanker, Stena Impero, sailing under a British flag, was boarded and captured by Iranian forces. The spokesman for Iran's Guardian Council, Abbas Ali Kadkhodaei, was quoted as describing the seizure as a "reciprocal action". This was presumed to be in reference to the seizure of an Iranian tanker bound for Syria, Grace 1, in Gibraltar a few days prior.

In 2020, France deployed about 600 troops at sea and in the air under the CTF474 to protect maritime trade, regional business, and to ease local tensions. Since the first week of April 2020, the operation combines the Dutch frigate Ruyter, the French frigate Forbin, and one French airplane ATLANTIC2 (ATL2).

2025

On 14 June, Iran reportedly issued a threat to block the strait in response to Israeli attacks targeting its military and nuclear infrastructure. The Financial Times reported that such action could cause oil prices to surge beyond the recent 7–14% increases, possibly exceeding $100 to $150 per barrel. This would likely fuel global inflation and contribute to an economic downturn. Analysts emphasized the vulnerability of regional exporters, noting that "Saudi Arabia, Kuwait, Iraq and Iran are wholly locked into one tiny passage for exports." The strait handles 18 to 19 million bbl (2.9 to 3.0 million m3) per day, nearly 20% of global oil consumption, including crude, condensates, and fuel. Analysts have warned that Iran could suffer severe consequences from any attempt to block the strait. "Iran's economy heavily relies on the free passage of goods and vessels through the seaway, as its oil exports are entirely sea-based," analysts from JP Morgan explained. Closing the strait could strain Iran's crucial energy trade with China, its only major oil customer. U.S. Secretary of State Marco Rubio also warned Iran against attempting to shut down the strait, stating that such a move would be "economic suicide" for the Islamic Republic, as the waterway is vital for its exports. On 17 June, two oil tankers collided in the strait, though reports did not suggest that this was a security-related incident. The vessels involved were the Front Eagle, carrying crude oil from Iraq to China, and the Adalynn, which was unladen and en route to the Suez Canal. Both caught fire on deck, but no oil spill occurred. All crew members aboard the Adalynn were safely evacuated by the UAE coast guard.

After the United States strikes on Iranian nuclear sites on 22 June, the Iranian Parliament voted to close the strait. A final decision rests with Iran's Supreme National Security Council. Revolutionary Guards commander Esmaeil Kousari confirmed that shutting the strait would be executed "whenever necessary", to protect national sovereignty and deter further foreign aggression. The potential closure of the strait, through which 20% of the world's oil supply transits, would significantly disrupt global energy markets. Such a move could cause oil prices to increase and risk destabilizing the global economy, given the strait's critical role as a maritime chokepoint for crude oil, liquefied natural gas, and other petroleum products. On 23 June 2025, oil prices were below $70 again (7% lower than on 20 June), indicating that the oil market viewed the U.S. strikes, and Iran's response (the strait remaining open, and 2025 Iranian strikes on Al Udeid Air Base), as inconsequential.

2026

Before the 2026 Israeli–United States strikes on Iran, ship insurance for the strait increased from 0.125% to between 0.2% and 0.4% of the ship insurance value per transit. For very large oil tankers, this is an increase of a quarter of a million dollars. By 9 March, insurance rates were reported to have increased by four to six times over the previous week, and the U.S. government began to help insurers under the Terrorism Risk Insurance Act. Within days of the conflict, tanker traffic through the strait collapsed, restricting shipments by more than 90%, around 10 million barrels per day of oil production. The restrictions on shipping in the Strait has led to disruptions that are raising energy and agricultural input costs worldwide.

On 28 February 2026, amid the 2026 Iran war and after the assassination of Iranian supreme leader Ali Khamenei, Iran's Revolutionary Guards began issuing VHFTooltip very-high-frequency transmissions stating that ship passages through the Strait of Hormuz were "not allowed". Although the closure is not legally binding, military and industry sources say that safety cannot be guaranteed, and many ships stayed in port or turned back, while at least 17 oil tankers continued traveling through the strait.

Strait of Hormuz transits dropping away in early 2026.

On 2 March, the Islamic Revolutionary Guard Corps officially confirmed that the Strait of Hormuz was closed and that any ship that entered the strait was to be set on fire. This came after several reports of Iranian attacks on ships passing into the Strait of Hormuz. However, a few ships still passed the strait unharmed. The next day, President Donald Trump stated that the U.S. Navy may escort oil tankers through the Strait of Hormuz.

On 12 March, three cargo vessels were hit in the Strait of Hormuz. This came on the same day as the release of 400 million barrels of oil announced by the International Energy Agency. It was also reported that Iran had deployed about a dozen mines in the Strait of Hormuz, halting the exports of oil and LNG.

On 15 March, President Donald Trump asked several nations—specifically China, France, Japan, South Korea and the United Kingdom, but also Canada and Australia—to send warships and assist in securing the Strait of Hormuz. Trump, noting that these nations are beneficiaries of the shipping route, pressured NATO and allies to help secure it following shipping disruptions. Most nations refused to assist, as they want a diplomatic de-escalation instead of war. The United Kingdom has offered limited cooperation in securing critical shipping routes; the broader refusal highlights a significant rift between Washington and its traditional partners.

Trump has warned that the planned summit with Chinese President Xi Jinping may be at risk if China does not assist the U.S. in securing the Strait of Hormuz. This crucial waterway, through which 20% of global oil passes, is facing disruptions due to ongoing tensions between the U.S., Israel, and Iran. Trump emphasized that China, which relies on the strait for 90% of its energy imports, should share the responsibility of keeping it open, rather than leaving it solely to the U.S. to secure.

As of 31 March 2026, Iran remains determined to assert control over the Strait of Hormuz, and has reportedly successfully blocked two Chinese ships.

British Prime Minister Keir Starmer, referring to the difficulty of reopening the Strait of Hormuz, said that if the war stops, we will need a negotiated agreement with Iran. West Point analysis warns that strait of Hormuz blockade will strangle US defense industry.

Ability of Iran to hinder shipping

Strait of Hormuz

Millennium Challenge 2002 was a major war game exercise conducted by U.S. armed forces in 2002. It simulated an attempt by a country (likely to be Iran) to close the strait. The assumptions and results were controversial. Iran's simulated strategy beat the materially superior U.S. armed forces.

A 2008 article in International Security contended that Iran could seal off or impede traffic in the strait for a month, and an attempt by the U.S. to reopen it would be likely to escalate the conflict. In a later issue, however, the journal published a response which questioned key assumptions and suggested a much shorter timeline for re-opening.

Moreover, due to Iran's own dependence on oil exports through the strait as well as imports, (due to its inability to refine oil on its own) a closure of the strait is unlikely. Not only Iran's own dependence on the strait for imports and exports is indicative that a prolonged closure is unlikely, but also the dependence of its allies on the trade that flows through it suggest the logistical infeasibility of such closure. A neoclassical-realist analysis describes Iranian policy regarding the strait as "double-faced": in non-existential threat environments Tehran tends to act as a security provider by keeping the strait open, whereas under threats perceived as existential it takes calculated risks and incorporates the waterway into a wider deterrence and brinkmanship strategy. This interpretation portrays Iran as a reactive actor that employs interference or brinkmanship to gain concessions and trigger de‑escalatory measures from the international community. This literature also emphasizes that Iran's strategy with respect to the strait is constrained by its own reliance on the waterway, that of key partners, material limits and sanctions, which lowers its freedom to take risks and suggests that any prolonged closure would be particularly damaging for Iran itself and its allies.

In December 2011, Iran's Navy began a ten-day exercise in international waters along the strait. Iranian Rear Admiral Habibollah Sayyari stated that the strait would not be closed during the exercise; Iranian forces could easily accomplish that but such a decision must be made at a political level. Captain John Kirby, a Pentagon spokesman, was quoted in December 2011 saying: "Efforts to increase tension in that part of the world are unhelpful and counter-productive. For our part, we are comfortable that we have in the region sufficient capabilities to honor our commitments to our friends and partners, as well as the international community." Suzanne Maloney, an expert at the Brookings Institution, said, "The expectation is that the U.S. military could address any Iranian threat relatively quickly." General Martin Dempsey, Chairman of the Joint Chiefs of Staff, said in 2012 that Iran "has invested in capabilities that could, in fact, for a period of time block the Strait of Hormuz." He stated, "We've invested in capabilities to ensure that if that happens, we can defeat that."

A May 2012 article by Nilufer Oral, a Turkish researcher of maritime law, concludes that both the UNCLOS, which came into effect in 1994; and the 1958 Convention on the High Seas would be violated if Iran followed through on its threat to block passage of vessels, such as oil tankers, and that the act of passage is not related in law to the imposition of economic sanctions. The article further asserts that a coastal state may prevent "transit or non-suspendable innocent passage" only if: 1) there is threatened or actual use of force, occurring during passage, against the sovereignty, territorial integrity, or political independence of a state bordering the strait; or 2) the vessel in any other way violates the principles of international law as embodied in the Charter of the United Nations.

As of 2013, the UNCLOS treaty had been ratified by 63 states, including most NATO-bloc and Soviet-bloc nations but with the notable exceptions of most of the OPEC and Arab League nations like Syria, Egypt, Jordan, Saudi Arabia, and Iran, as well as China, North Korea, and South Korea. As of February 2026, 157 sovereign states, including the EU are parties, including all major powers except the United States, which has not ratified the treaty.

Alternative shipping routes

Strait of Hormuz

A map of the Habshan–Fujairah oil pipeline and the East–West Crude Oil Pipeline

By 2025, around 15 million barrels (2.4 million cubic metres) of oil per day were transported through the strait. Onshore pipelines have a maximum capacity of around 3 million barrels. All LNG must be transported by ship through the strait.

In June 2012, Saudi Arabia reopened the Iraq Pipeline through Saudi Arabia (IPSA), which was confiscated from Iraq in 2001 and travels from Iraq across Saudi Arabia to a Red Sea port. It has a capacity of 1.65 million barrels (262,000 m3) per day.

In July 2012, the UAE began using the new Habshan–Fujairah oil pipeline from the Habshan fields in Abu Dhabi to the Fujairah oil terminal on the Gulf of Oman, effectively bypassing the Strait of Hormuz. It has a maximum capacity of around 2 million barrels (320,000 m3) per day, over three-quarters of the UAE's 2012 production rate. The UAE is also increasing Fujairah's storage and off-loading capacities.

The UAE is building the world's largest crude oil storage facility in Fujairah with a capacity of holding 14 million barrels (2,200,000 m3) to enhance Fujairah's growth as a global oil and trading hub. The Habshan – Fujairah route secures the UAE's energy security and has the advantage of being a ground oil pipeline transportation which is considered the cheapest form of oil transportation and reduces insurance costs as oil tankers would no longer enter the Persian Gulf.

In a July 2012 Foreign Policy article, Gal Luft compared Iran and the Strait of Hormuz to the Ottoman Empire and the Dardanelles, a choke point for shipments of Russian grain a century ago. He indicated that tensions involving the Strait of Hormuz are leading those currently dependent on shipments from the Persian Gulf to find alternative shipping capabilities. He stated that Saudi Arabia was considering building new pipelines to Oman and Yemen, and that Iraq might revive the disused Iraq–Syria pipeline to transport crude oil to the Mediterranean. Luft stated that reducing Hormuz traffic "presents the West with a new opportunity to augment its current Iran containment strategy."