Water mines, speedboats, and kamikaze drones: how Iran could block the Strait of Hormuz

Iran’s threat to close the Strait of Hormuz — a maritime corridor through which about one-fifth of the world’s oil supply flows — has once again raised global concerns. On Monday, the European Union’s foreign policy chief, Kaja Kallas, called the possibility “extremely dangerous” and warned that such an action “would be bad for everyone.”

But what does closing the Strait of Hormuz mean? And how can a single country attempt to interrupt one of the most vital commercial routes of the global economy, even in international waters?
Although part of the strait is under the jurisdiction of Iran and Oman, the lanes used by commercial vessels are considered international waters under UN maritime law.

On paper, that would legally prevent Iran from blocking it. But in practice, geography and Iran’s military power tell a different story.

At first glance, the Strait of Hormuz seems too wide to be closed by a single country, stretching over 30 kilometers at its narrowest point. However, the massive oil tankers and cargo ships that cross the area daily don’t sail freely anywhere they please.

They follow two defined maritime corridors, known as traffic lanes, established internationally to organize the flow and prevent accidents. Each lane is only three kilometers wide, with a three-kilometer buffer zone between them. One corridor is used to enter, and the other to exit the Persian Gulf — a two-way maritime road.

In other words, all global commercial traffic that depends on the Strait of Hormuz is funneled through two extremely vulnerable navigation corridors. They are narrow, predictable zones — and lie squarely within range of Iranian missiles, drones, and mines.

Over the years, Iran has strengthened its coastal military arsenal and adopted technologies that could turn the region into a minefield. One of the most viable strategies for disrupting maritime traffic would be the deployment of naval mines.

Small, silent, and hard to detect, they can be dropped by submarines, ships, or even helicopters at key choke points. In addition to mines, Iran maintains mobile anti-ship missile batteries along the Persian Gulf coast. Models like the Noor and Khalij Fars have enough range to hit vessels in open navigation. With a mountainous coastal topography, these platforms can be easily relocated and concealed, making them difficult for Western forces to neutralize.

The Iranian Revolutionary Guard is also known for its fleet of fast attack boats and kamikaze drones, capable of swarming larger ships, intimidating them, or even launching coordinated “swarm” attacks that are hard for commercial or military vessels to defend against. During the recent escalation in the Middle East, Israel-linked ships were hit by drones and missiles of Iranian origin, showing that Tehran has the ability to project power beyond its borders.

The Strait of Hormuz links the Persian Gulf to the Gulf of Oman and, from there, to the Indian Ocean. Around 17 million barrels of oil pass through it daily, along with liquefied natural gas from Qatar. Even without an official blockade, Iran has shown it can selectively halt naval traffic.

In 2019, the country seized British oil tankers in retaliation for the capture of an Iranian vessel in Gibraltar. More recently, amid the conflict with Israel, ships linked to Western allies were also temporarily prevented from transiting through the Gulf.

In 1988, an American frigate was damaged by an Iranian mine. In retaliation, U.S. forces destroyed three Iranian warships and two surveillance platforms. In July of the same year, a U.S. warship shot down an Iranian commercial airliner with two missiles, killing all 290 civilians on board, including 66 children. According to the White House, the crew mistook the aircraft for a fighter jet.

Given the economic importance of the passage, Iran’s most powerful tool might not be its mines or missiles — but its ability to manipulate global market psychology. The mere threat of closing the strait can spark panic in oil exchanges. Ships reroute, insurance rates skyrocket, and oil prices react immediately. In response, the international community maintains constant surveillance in the region. The United States and the United Kingdom operate permanent naval patrols in the Persian Gulf to ensure freedom of navigation. As such, any real attempt by Iran to block the strait could trigger a direct military response.

For Iran, closing the Strait of Hormuz is risky — but using the threat as a political and military card is a tactic the country has practiced for decades. In this context, Kaja Kallas’s statement from the European Union echoes a fear shared by diplomats and economists alike: a single misstep could ignite not only the Middle East but the global economy.

Source: O Globo

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