Iran's "Mosquito Fleet": How a swarm of small boats confronts the US Navy in the Strait of Hormuz

Iran's "Mosquito Fleet" consists of a flotilla of small, high-speed attack boats, captured in this image taken in southern Iran in 2024 during a naval parade. Photo: Nurphoto via Getty Images

"Harass, Swarm, Confuse, and Disrupt Shipping"

The fleet of small, high-speed attack boats was created by the Iranian regime in the 1980s during the Iran-Iraq War. Although Iran was fighting Iraq, the "Tanker War" of the 1980s also affected the Persian Gulf, forcing the US to intervene to protect oil shipments.

Clashes with the US Navy led to heavy losses for Iran's conventional navy. After this, Iran's fleet of small boats became part of a military doctrine developed to confront more powerful naval states.

At the same time, the small boat fleet is only part of Iran's broader strategy, which also includes missiles, drones, mines, shore-based launchers, and attacks by pro-Iranian groups in neighboring countries. This fleet is controlled by the influential Islamic Revolutionary Guard Corps (IRGC) and is designed not for traditional naval combat, but to "harass, swarm, confuse, and disrupt shipping," says Saeed Gholkar, an associate professor at the University of Tennessee at Chattanooga and a senior advisor to the non-profit organization United Against Nuclear Iran (UANI), which opposes the Iranian regime.

"The IRGC understands that it cannot defeat the US in a conventional naval war," he adds.

Instead, they seek to increase the costs and risks for companies engaged in transit through the Persian Gulf by attacking commercial tankers and making the Strait more dangerous for shipping.

According to experts, the fleet's tactics include firing warning shots near merchant vessels, laying naval mines, and attacking in groups of boats rushing at high speed from different directions. High-speed attack boats are often equipped with machine guns, rockets, or anti-ship missiles. While many of them were designed and manufactured by the Iranian state, some were converted from civilian vessels, including former fishing trawlers.

"These boats are inexpensive and easy to replace," writes Can Kasapoğlu, a senior non-resident fellow at the Hudson Institute — a conservative think tank in Washington — in a recent report.

According to Kasapoğlu, this allows Iran to threaten merchant and military vessels "at relatively low cost, while putting the opponent's expensive assets and the global maritime economy at risk."

Experts believe that the ultimate goal of these operations is to compel Washington to abandon war with Tehran and halt future attacks.

Because many of these boats sit low in the water, they are difficult to detect with radar until they are close, so effective patrolling requires constant surveillance using drones, helicopters, or patrol aircraft.

The exact number of this fleet is unknown, partly because many of the boats are hidden in caves, coves, and underground tunnels along Iran's southern coast. However, estimates vary from 500 to over a thousand. The Iranian regime regularly conducts naval exercises involving the "mosquito fleet."

Павялічыць

"This fleet is not designed for traditional naval combat, but to harass, swarm, confuse, and disrupt shipping," says Saeed Gholkar. Photo: Nurphoto via Getty Images

"Naval Guerrilla Warfare"

Experts often refer to Iran's actions as "guerrilla warfare at sea." Saeed Gholkar says that despite the US Navy's ability to destroy Iranian high-speed boats when they venture into open waters, the IRGC tries to avoid open combat encounters.

"The IRGC tries to avoid direct confrontation and instead uses 'hit-and-run' tactics, swarm attacks, mines, drones, missiles, and small boats to increase costs for the US and commercial shipping," says Gholkar.

Iran can quickly and inexpensively replace destroyed boats, while the US and its allies are forced to deploy expensive ships and aircraft to ensure the safety of commercial shipping.

Experts note that even without destroying vessels, creating the appearance of serious danger can lead to higher insurance premiums and force companies to avoid this route. Even the threat of naval mines can slow down or completely halt shipping. Mine clearance of a waterway is a slow process.

Is Iran's strategy working?

The volume of shipping through the Strait of Hormuz has sharply fallen compared to pre-war levels. The Hormuz Strait Monitor platform, designed to track vessel movements through the strait in real-time, shows that approximately 10 vessels pass through this waterway daily. This is about 8% of its usual daily average of 60 vessels.

According to data from the Royal Navy team monitoring the situation in the region, overall traffic remains more than 90% below pre-war levels. A brief increase in activity was observed on April 8, when the US, Israel, and Iran agreed to a ceasefire. However, the situation dramatically changed a few days later after the US imposed its own blockade on the import and export of goods from Iran.

And attacks in the strait continue. Last week, the UK Maritime Trade Operations (UKMTO), which monitors international maritime routes, reported that a bulk carrier was "struck by an unknown projectile" approximately 23 nautical miles (43 kilometers) northeast of the Qatari capital, Doha. A small fire broke out on board, but there were no casualties. Later, the Iranian news agency Fars reported that the bulk carrier was sailing under a US flag and belonged to the United States.

According to estimates by the UN International Maritime Organization, approximately 1,500 vessels and 20,000 crew members continue to suffer from the blockade. The reduction in the volume of oil passing through the strait has been one of the reasons for what some experts call the largest oil supply market shock in history, resulting in oil prices reaching near-record highs.

• 2
• 2
• 0
• 2
• 1
• 0
• 2
• 0