Arming the Strait of Hormuz

The Hormuz is one of the world's most critical maritime chokepoints, with its narrowest point only about 21 nautical miles wide, and shipping lanes, through which ships transit, are even narrower. Roughly 20-30 per cent of global seaborne oil passes through it, which translates to about 140 ships on a daily basis. Iran and Oman are the two nations that abut the strait, and the geography and topography of the region gives Iran unassailable advantage in controlling the transit through the Hormuz.

For India, almost 60 per cent of its total hydrocarbon imports pass through the Hormuz and the international norm of allowing unhindered transit passage through critical chokepoints was accepted as the global practice, in consonance with maritime law, derived from the 1982 UNCLOS (UN law of the seas).

Iran decided to exercise its most consequential strategic leverage — closure of the Hormuz in early March and this was a major departure from earlier practice. The West Asian region is not new to war and conflict, yet Iran had not historically imposed or achieved a full, sustained physical closure of the Hormuz prior to 2026.

In previous decades, despite frequent threats during the 1980s Tanker War (Iran-Iraq War), the 2011–2012 sanctions crises, the 2018–2019 tensions during Trump 1.0 and the 2025 Israeli attack on Iran, the strait remained open. In some cases, Iran disrupted traffic through gun-boat attacks, mining and harassment of the adversary, but did not prevent all transit.

However, in response to the US-Israel military strikes on Iran, which included the assassination of former supreme leader Ayatollah Ali Khamenei, Iran retaliated by disrupting and effectively blocking much of the transit through the Hormuz. Effective disruption began in early March and shipping traffic dropped sharply from 100 to 140 ships per day to near zero. This was largely due to Iranian military attacks, which in 2026 included drones and shore-based missiles, apart from the traditional arsenal of gunboats and mine-laying that Iran had used in the past.

An official of the Islamic Revolutionary Guard Corps (IRGC) declared the strait “closed” on March 2 with a formal announcement on March 4, stating it was closed and threatening to attack ships attempting to pass. Iran targeted vessels linked to adversaries (US and Israel) and imposed restrictions. Ship traffic was largely blocked from this period onward, with selective passages (some Iranian-linked ships or those paying fees), but there was widespread avoidance due to the military risks and the high insurance costs that inhibited normal mercantile commerce. The negative impact on the global energy supply chain and downstream linkages such as fertilisers was considerable.

There was some hope that Pakistan-enabled negotiations would lead to an equitable and consensual cessation of hostilities, but this was belied when the talks failed. The Iranian control over the Hormuz and restricting transit passage was no doubt a transgression of international law, but sanctity for law had already been trampled by Israel and the US when the war began by their unilateral acts of aggression and political assassinations.

To apply pressure on Iran and compel it to open the strait, the US in turn decided to add another layer of militarisation to the Hormuz and imposed a naval blockade on Iranian ports effective since April 13. The US enforced the blockade primarily through naval surface forces from US Central Command (CENTCOM), supported by air and amphibious assets. The operation (which is ongoing at the time of writing) focuses on intercepting, redirecting, or disabling vessels attempting to enter or exit Iranian ports/coastal areas while allowing neutral transit through the Strait of Hormuz.

The principal naval platforms include aircraft carriers and carrier strike groups that include guided missile destroyers – which is a formidable naval force. The US deployed three carriers in the region (a high concentration of transborder military capability), providing air superiority, strike capability, intelligence, surveillance, reconnaissance and command and control.

The impasse continues in May, with the Hormuz being closed by Iran, thereby aggravating an already disrupted global energy market and the US maintaining the naval blockade that seeks to strangulate the Iranian economy.

In summary, the tactical situation in the Hormuz is that of Iran, which has developed an asymmetric “anti-access/area denial” (A2/AD) strategy relying on geography, quantity over quality (swarm technique) and cost-imposing tactics rather than symmetric naval power. On the other side, the US and allies have overwhelming naval superiority and remain focused on freedom of navigation, escort operations and countering Iranian threats, but with doubtful impact, since shipping traffic remains at a trickle. 

Iran’s primary mechanisms are the use of mines and swarm tactics within the Strait of Hormuz. Between the regular navy and the IRGC, Iran has one of the world's largest stockpiles of mines estimated to be about 5,000 plus. Many of them are domestically produced and include moored, drifting, and advanced influence mines.

Small boats and submarines can rapidly lay them in shipping lanes, creating persistent hazards that require slow, dangerous clearance operations. Mines were used or threatened by Iran in past tensions, but reports suggest that the density of the current mine-laying is more lethal and wide-spread in the Strait and the entry to the Hormuz.

This poses a high degree of threat and uncertainty to the ships in the region, both merchant and naval and the de facto situation is that the US Navy, despite its overwhelming superiority, cannot operate in the Strait with the operational confidence that it can in a mine-free maritime domain.

Iran’s claim of laying sea mines, whether true or not, has introduced a complex and lethal navigation hazard and whenever there is a total cessation of hostilities, the Hormuz will have to be cleared of all mines. This will be a very time-consuming task and will need international cooperation.

The numbers involved are relatively small, it is estimated that around a few dozen but less than 30 mines have been laid/scattered by Iran. The figures are very imprecise and according to the US and other intelligence assessments, the exact number is uncertain and there will be no official number in the public domain.

Iran is reported to have laid a few mines in early March and later, as the conflict progressed into April, additional mines were laid but on a limited and haphazard scale. Iran has struggled to track or remove all of them due to poor record-keeping, drifting, and use of small vessels. This will complicate efforts to reopen the Strait in a full and safe manner. Iran has apparently apprised global maritime regulators that its different agencies did not map the distribution pattern comprehensively due to the conflict conditions.

How difficult is it to clear such mines? Clearing mines from the Strait of Hormuz would be extremely difficult, time-consuming, and dangerous. US military assessments cite as much as six months for full clearance — once there is a ceasefire. Apart from the lack of an accurate  global positioning system-enabled chart indicating where the mines were first laid, the local maritime geography compounds the difficulties.

This Strait connects the north Arabian Sea to the Persian Gulf, experiences strong tidal currents and has varying depths, leading to a three-dimensional domain, with time as the fourth element, since the mines may drift with high and low tides. Sedimentation could lead to mines getting buried  and the area to be covered is considerable. The Hormuz strait itself is about 11,000 square kilometres (sq km) and the larger Persian Gulf it connects to is more than 240,000 sq km.

Mines laid by Iran would include direct contact, influence (triggered by acoustic/magnetic/pressure) and perhaps more advanced variants. Detecting and neutralising them requires slow, methodical work. Proving that an area is fully clear of mines and meets global insurance standards will be even harder than detection. However, for partial resumption of shipping traffic, swept channels, free of mines, could be created and prominently marked with marker buoys.

Consequently, the mine clearing effort will need a capability that Iran does not possess currently. The one nation that is most capable by way of advanced mine clearing and mine countermeasures (MCM) assets is the US. Russia and China  also have proven capability but are not at the same level as the US. Other nations include major powers of the North Atlantic Treaty Organization, Japan and South Korea.

India does not have any significant mine-clearance capability, and this is a void that has existed for over two decades and will have to be filled. India’s MCM gap is a recognised vulnerability, especially given its long coastline, major ports and regional threats. Plans include induction of indigenously built MCM vessels, but they may be inducted only in the next 10 years.

The current closure and militarisation of the Hormuz could be interpreted as a case of critical maritime geography (chokepoints) being used for advancing combat goals by both adversaries. This is not new and historically, from ancient times to the modern era, controlling or denying chokepoints (straits, canals, narrows) has been a classic maritime strategy in economic warfare and naval conflict.

In the post-1945 era, that is after World War II, the most consequential parallel is the Suez Canal’s closure for eight years following the 1967 Six-Day War.

Egypt closed the canal in June 1967, shortly after the war began. It became the frontline between Egyptian and Israeli forces, when Israel occupied the Sinai Peninsula, including the east bank of the canal. Egypt sank ships, laid mines, and blocked the waterway deliberately as part of the conflict.

The Suez remained closed for eight long years until June 1975 (after the 1973 Yom Kippur War and subsequent negotiations) and this forced ships to reroute around the Cape of Good Hope, thereby adding thousands of miles, higher costs, and delays.

Markets responded to the Suez closure by spurring the development of larger supertankers and alternative pipelines and related infrastructure. The Sumed pipeline in Egypt that connects the Red Sea to the Mediterranean Sea was commissioned in 1977 and provided an alternative to the Suez Canal.

Currently, alternate options to reduce dependency on the Hormuz are gathering traction. Major oil producers like Saudi Arabia and the United Arab Emirates have switched to pipelines and by-passing the Hormuz is being explored by all the major stakeholders.How soon this will happen is moot and in the interim. Brent will fluctuate to levels above $100 and Hormuz-induced belt-tightening across the board will become the new norm.

Epic Fury has morphed into epic hardship and alas, the global South will bear the brunt.