Strait of Hormuz

At its narrowest point, the Strait of Hormuz measures just 21 nautical miles (39 kilometers) across. Through this slender passage flows approximately 21 million barrels of oil per day—roughly 21% of global petroleum consumption—and about 20% of the world’s liquefied natural gas (LNG) exports. In dollar terms, an estimated $1.2 billion worth of oil and gas transits Hormuz every 24 hours. No other geographic feature has such concentrated importance for the world economy. alfred-mahan’s insight that chokepoints confer disproportionate strategic leverage finds no better illustration than this narrow passage between Iran and the Arabian Peninsula.

Geographic Position¶

The Strait of Hormuz connects the Persian Gulf to the Gulf of Oman and, from there, to the Arabian Sea and Indian Ocean—the maritime highway linking the energy-rich Middle East to the consuming economies of Asia and beyond.

Physical Features¶

The strait is bounded by:

• Iran to the north, with approximately 1,100 miles of Persian Gulf coastline and numerous islands projecting into the strait
• Oman (the Musandam Peninsula, a small exclave separated from the rest of Oman by UAE territory) and the United Arab Emirates to the south
• Qeshm Island (Iran’s largest island, 1,491 square kilometers) and Hormuz Island dominate the northern approaches
• Two designated shipping lanes, each approximately 2 miles (3.2 km) wide, separated by a 2-mile buffer zone, established under the International Maritime Organization’s Traffic Separation Scheme

The strait’s depth ranges from 60 meters (197 feet) in the shipping lanes to shallower areas near the coasts. The navigable channels pass closer to the Iranian shore than the Arab side—vessels must transit within 20-30 miles of Iranian territory, well within range of coastal defense systems. This geographic asymmetry gives Iran inherent tactical advantages.

The Inbound and Outbound Lanes¶

International shipping follows established patterns:

• Inbound lane (into the Persian Gulf): Ships enter through a lane on the Omani side
• Outbound lane (exiting the Gulf): Heavily laden tankers depart through a lane closer to Iran
• Average transits: Approximately 40-50 tankers pass through daily, plus numerous other commercial vessels and warships

The entire transit takes approximately 8-10 hours at typical tanker speeds, during which vessels are vulnerable to threats from either shore or from the sea itself.

Why Hormuz Matters¶

Oil Transit¶

The Persian Gulf contains approximately 48% of proven global oil reserves—an estimated 800 billion barrels. The major producers depend on Hormuz for the vast majority of their exports:

Daily transit volumes typically exceed 21 million barrels per day—enough oil to fill approximately 28 Very Large Crude Carriers (VLCCs, each carrying 2 million barrels). The primary consumers of this oil:

• Asia: China imports approximately 7-8 million barrels per day through Hormuz (about 40% of its total imports); Japan approximately 3 million bbl/day (85% of its imports); South Korea approximately 2.5 million bbl/day (75%); India approximately 2.5 million bbl/day (60%)
• Europe: Approximately 3 million bbl/day transits Hormuz bound for European refineries, though Europe has diversified toward North Sea, African, and American sources
• United States: Direct imports are minimal since the shale revolution made the U.S. the world’s largest oil producer, but American consumers still feel the impact of global price spikes

Limited Alternatives¶

There are limited alternatives to Hormuz transit, and none can substitute for tanker traffic at scale:

• East-West Pipeline (Saudi Arabia): The Petroline can carry approximately 5 million bbl/day from the Eastern Province to the Red Sea port of Yanbu, bypassing Hormuz—but this is less than half of Saudi production
• Abu Dhabi Crude Oil Pipeline (UAE): The 1.5 million bbl/day Habshan-Fujairah pipeline bypasses Hormuz to the Gulf of Oman, providing some insurance against closure
• Iraq-Turkey Pipeline: Carries approximately 500,000 bbl/day to the Mediterranean, but this serves only Iraqi exports
• Proposed alternatives: Various pipeline projects through Pakistan, Iran, or overland to the Mediterranean have been proposed but face political, security, and cost obstacles

Even operating at maximum capacity, bypass routes could handle perhaps 6-7 million bbl/day—less than a third of current Hormuz transit volumes.

LNG Exports¶

Qatar, the world’s largest or second-largest LNG exporter (competing with Australia), ships virtually all of its 77 million tons per year through Hormuz—approximately 20% of global LNG trade. Qatar’s North Field, the world’s largest natural gas field (shared with Iran), feeds enormous liquefaction facilities that load LNG tankers bound for Asia and Europe.

The UAE and Oman are expanding LNG production. Combined Gulf LNG exports exceed 100 million tons annually. Closure of the strait would devastate global gas markets, particularly in Asia where LNG prices can spike 300-400% during supply disruptions.

The Iranian Position¶

Iran’s control of the northern shore gives it significant leverage over one of the world’s most critical waterways—leverage Tehran has repeatedly demonstrated willingness to use.

Geographic Advantages¶

Iran’s geography provides inherent tactical benefits:

• The main shipping lanes pass through waters 20-30 miles from Iranian territory—well within range of coastal weapons. Tankers in the outbound lane are particularly exposed to the Iranian mainland.
• Iranian islands extend Tehran’s reach into the strait: Qeshm Island (population 150,000) hosts military facilities; Hormuz Island lies at the strait’s narrowest point; Greater and Lesser Tunb and Abu Musa (seized from the UAE in 1971) project Iranian sovereignty into the southern approaches.
• Bandar Abbas, Iran’s largest port (population 500,000), sits at the northern entrance to the strait, hosting both commercial facilities and naval bases.
• The Iranian Navy and Islamic Revolutionary Guard Corps Navy (IRGCN) maintain substantial presence. The regular navy operates frigates, corvettes, and submarines; the IRGCN specializes in fast attack craft, mines, and asymmetric warfare.

Threatened Closures¶

Iran has repeatedly threatened to close Hormuz in response to economic pressure or military attack:

• 1984: During the Iran-Iraq War, Iran declared portions of the Gulf a war zone
• 2008, 2011-12: Iranian officials threatened closure in response to potential military action or oil sanctions
• 2018-19: Following U.S. withdrawal from the JCPOA nuclear deal, Iran explicitly warned that if it could not export oil, no one would
• 2024: Renewed threats amid regional tensions following the Gaza conflict

Whether Iran could sustain closure is debated. A full blockade would require preventing determined efforts by the U.S. Navy and allied forces to reopen the strait—likely beyond Iran’s conventional capability. But even temporary disruption lasting days or weeks would shock global markets and impose enormous costs.

Asymmetric Capabilities¶

Iran has invested billions in capabilities specifically designed to threaten shipping and impose costs on superior naval forces:

• Anti-ship missiles: Iran possesses thousands of cruise missiles (including the Noor, Qader, and Khalij Fars families) and has developed anti-ship ballistic missiles. Ranges extend from 30 km to over 700 km, enabling strikes from deep inland.

• Naval mines: Iran is estimated to possess 5,000-6,000 naval mines of various types—contact mines, influence mines, and advanced rising mines. Mines are cheap (as little as $1,000 each), difficult to detect, and psychologically powerful.

• Fast attack craft: The IRGCN operates 200+ small fast attack craft, some armed with missiles, capable of swarming tactics against larger vessels. These boats can launch from multiple ports and operate in confined waters where larger warships are vulnerable.

• Submarines: Iran operates three Russian-built Kilo-class diesel submarines (capable of mine-laying and torpedo attacks) plus approximately 20 domestically produced mini-submarines (Ghadir and Nahang classes).

• Shore-based systems: Artillery, rockets, and coastal defense missiles positioned along the Iranian coast can engage vessels transiting the strait.

A conventional military confrontation with the U.S. Navy would not end well for Iran—American forces would eventually prevail. But Tehran’s ability to inflict damage, sink tankers, disrupt shipping, and impose costs is substantial. The question is whether deterrence holds.

Strategic Scenarios¶

Temporary Disruption¶

Even short-term disruption—from military conflict, accidents, or political crisis—would:

• Spike oil prices immediately (the “fear premium”)
• Strain global oil reserves
• Force expensive rerouting of tankers
• Destabilize energy-dependent economies

The 2019 attacks on tankers near Hormuz, attributed to Iran, demonstrated the market’s sensitivity. Oil prices jumped despite minimal actual supply disruption.

Extended Closure¶

A sustained closure would constitute a global economic crisis:

• Oil prices would reach unprecedented levels
• Asian economies would face energy emergencies
• Global recession would likely follow
• Military intervention would become probable

For this reason, the United States maintains significant naval forces in the region and has repeatedly stated that keeping Hormuz open is a vital interest.

Mine Warfare¶

Mining the strait is perhaps the most likely Iranian asymmetric option. Mines are cheap, difficult to clear, and psychologically powerful—insurers will not cover tankers transiting mined waters, halting traffic even if the mines pose limited actual danger.

The US maintains minesweeping capabilities, but clearing operations in contested waters would be challenging and time-consuming.

The American Military Presence¶

The United States Fifth Fleet, headquartered at Naval Support Activity Bahrain since 1995 (though American naval presence in the Gulf dates to 1949), is specifically tasked with maintaining freedom of navigation in the Gulf and Hormuz.

Forces and Capabilities¶

• Aircraft carrier strike groups: One or more CSGs typically operate in or near the Gulf, each comprising an aircraft carrier (5,000 personnel, 60+ aircraft), cruisers, destroyers, and submarines. Carrier air wings can strike targets throughout the region within hours.

• Guided missile cruisers and destroyers: Aegis-equipped surface combatants provide air defense, strike capability with Tomahawk cruise missiles (1,000+ mile range), and ballistic missile defense.

• Minesweepers: The U.S. maintains approximately 4 Avenger-class mine countermeasures ships in the region, plus MH-53E Sea Dragon helicopters for mine hunting—though critics argue this capability is inadequate for the mine threat.

• Patrol craft: Cyclone-class patrol coastal ships and other small combatants conduct maritime security operations and presence patrols.

• Air bases: Al Udeid Air Base in Qatar hosts approximately 10,000 U.S. personnel and serves as forward headquarters for U.S. Central Command air operations; additional facilities in the UAE, Kuwait, and Bahrain extend American reach.

The Carter Doctrine¶

This presence reflects the judgment, formalized by President Jimmy Carter on January 23, 1980, that the Persian Gulf is a vital American interest warranting military commitment:

“An attempt by any outside force to gain control of the Persian Gulf region will be regarded as an assault on the vital interests of the United States of America, and such an assault will be repelled by any means necessary, including military force.”

Spoken in the aftermath of the Soviet invasion of Afghanistan and the Iranian Revolution, the Carter Doctrine has guided American policy for over four decades. The Reagan administration implemented it through Operation Earnest Will (1987-88); the Bush administration through the Gulf War (1991); subsequent administrations through continuous naval presence and periodic confrontations with Iran.

Multinational Operations¶

The U.S. does not operate alone. The Combined Maritime Forces, headquartered in Bahrain, brings together navies from over 30 nations. Specific task forces address piracy (CTF-151), maritime security (CTF-152), and counterterrorism (CTF-150). British, French, Australian, and other allied warships regularly transit the strait and operate in the Gulf.

Regional Dynamics¶

Arab Gulf States¶

Saudi Arabia, the UAE, Kuwait, and others depend on Hormuz for their economic survival—oil exports fund their governments and societies. They have invested in:

• Alternative pipeline routes (limited capacity)
• Strategic oil reserves
• Hosting American and allied military forces
• Their own naval and air capabilities

The UAE, in particular, has built a pipeline bypassing Hormuz to the port of Fujairah, providing some insurance against closure.

Oman¶

Oman occupies a unique position. The Musandam Peninsula gives it sovereignty over the southern shore of the strait, yet Oman has maintained cordial relations with Iran. This neutrality has made Muscat a back-channel for diplomacy.

China and Asian Importers¶

China receives approximately 40% of its oil through Hormuz. This dependence creates a strategic vulnerability that Beijing is keenly aware of—and one reason China has pursued overland energy routes through Central Asia, pipelines from Russia, and investments in alternative suppliers.

Japan and South Korea, with virtually no domestic oil production, are even more dependent and have aligned closely with American security guarantees.

Historical Incidents¶

The Tanker War (1984-1988)¶

The Iran-Iraq War (1980-1988) produced the most sustained combat in the strait’s modern history. Both sides attacked tankers to damage the other’s economy—Iraq targeting Iranian oil exports, Iran retaliating against ships serving Iraq’s Gulf Arab supporters.

The “Tanker War” phase escalated through 1984-88:

• Over 400 ships attacked: Both sides used missiles, mines, and aircraft. Approximately 200 sailors died; hundreds of vessels were damaged or destroyed.
• Operation Earnest Will (1987-88): The U.S. reflagged Kuwaiti tankers with American flags and provided naval escorts—the largest naval convoy operation since World War II.
• USS Stark incident (May 17, 1987): An Iraqi Mirage F1 fired two Exocet missiles at the American frigate, killing 37 sailors. Iraq apologized; the U.S. accepted compensation.
• Iran Air Flight 655 (July 3, 1988): The USS Vincennes shot down an Iranian Airbus A300 over the strait, killing all 290 passengers and crew. The U.S. maintained the ship’s crew mistook the airliner for an attacking fighter; Iran called it deliberate murder.
• Operation Praying Mantis (April 18, 1988): Following the mining of USS Samuel B. Roberts, U.S. forces attacked Iranian oil platforms and engaged the Iranian Navy, sinking or damaging half of Iran’s operational fleet—the largest American naval surface engagement since World War II.

The Tanker War demonstrated both the vulnerability of Gulf shipping and the limits of Iranian capability against determined American intervention.

Post-2019 Tensions¶

Following U.S. withdrawal from the JCPOA nuclear deal (May 2018) and reimposition of “maximum pressure” sanctions:

• Tanker attacks (May-June 2019): Four tankers were attacked near Fujairah (May 12); two more were struck in the Gulf of Oman (June 13). The U.S. attributed the attacks to Iran’s IRGC; Iran denied responsibility.
• Stena Impero seizure (July 19, 2019): Iranian forces seized the British-flagged tanker in the strait, holding it for two months in apparent retaliation for British seizure of an Iranian tanker off Gibraltar.
• RQ-4 Global Hawk shootdown (June 20, 2019): Iran shot down a $220 million American surveillance drone over or near the strait. President Trump ordered, then cancelled, retaliatory strikes with planes in the air.
• Near-miss with war (January 2020): U.S. assassination of IRGC Commander Qasem Soleimani in Baghdad and Iranian missile strikes on American bases in Iraq brought the two countries to the brink of open conflict.

These incidents demonstrated that tensions in the strait can escalate rapidly and that both sides possess the capability—and potentially the will—to use force.

Future Scenarios¶

Nuclear Iran¶

An Iran with nuclear weapons would alter the Hormuz calculus. Tehran might calculate that nuclear deterrence provides cover for more aggressive actions in the strait, while adversaries might be more reluctant to respond militarily.

Energy Transition¶

As the world shifts away from fossil fuels, Hormuz’s importance will gradually decline. However, the transition will take decades, and during that period, oil will remain critical. Natural gas may actually increase in importance as a “bridge fuel.”

Regional Realignment¶

The Abraham Accords and shifting alignments in the Middle East could reduce tensions—or could isolate Iran further, making it more likely to use Hormuz as leverage.

Conclusion¶

The Strait of Hormuz illustrates a fundamental geopolitical truth: chokepoints matter. The physical configuration of the earth’s surface creates points where traffic must concentrate, and those who control such points possess leverage disproportionate to their other resources.

For all the talk of a “flat world” enabled by technology, the barrel of oil that powers the global economy still must pass through a 21-mile gap between Iran and Arabia. Until that fundamental fact changes, Hormuz will remain one of the most strategically significant places on earth.

Sources & Further Reading¶

• “The Prize: The Epic Quest for Oil, Money & Power” by Daniel Yergin — The Pulitzer Prize-winning history of the oil industry that explains why the Persian Gulf and Hormuz became the fulcrum of global energy geopolitics.
• “The Twilight War: The Secret History of America’s Thirty-Year Conflict with Iran” by David Crist — Reveals the covert confrontations and near-misses in the Gulf that have shaped the current standoff over Hormuz.
• “Energy and Security in the Persian Gulf” by Kenneth Katzman (Congressional Research Service) — Authoritative analysis of the military balance and threat assessments that drive American policy in the region.
• “The Tanker War: America’s First Conflict with Iran, 1987-88” by Lee Allen Zatarain — Detailed account of the last major naval combat in the Gulf, offering lessons for potential future confrontations.
• “The Influence of Sea Power upon History” by Alfred Thayer Mahan — The foundational text explaining why chokepoints like Hormuz confer strategic leverage disproportionate to their geographic scale.