Hormuz: Naval Drones and the Strait's New Weapons

Roughly one fifth of the world's oil consumption and a similar share of liquefied natural gas trade pass through the Strait of Hormuz, according to the International Energy Agency and the U.S. Energy Information Administration. Barely 39 kilometres wide at its narrowest point, with shipping lanes of about 3 kilometres in each direction, it is the planet's most important energy chokepoint. And for the past decade it has also been the laboratory where some of the newest naval weapons are being tested: surface drones, unmanned underwater vehicles, fast-boat swarms and a new generation of anti-ship missiles.

This article examines which systems are documented, which are unverified announcements and where uncertainty persists. As always when discussing Iranian military capabilities, propaganda — on all sides — demands caution.

The setting: geography that multiplies small weapons

Hormuz is a textbook case of geography empowering asymmetric warfare. The transit lanes pass through Iranian and Omani territorial waters; the Iranian coast offers hundreds of coves, islands and dispersed facilities from which to operate. A 300-metre tanker can neither manoeuvre nor accelerate: it is a slow, predictable target in a compulsory corridor.

Iran structures its naval forces in two parallel services — the regular Navy (IRIN) and the Revolutionary Guard's Navy (IRGCN) — a duality the U.S. Office of Naval Intelligence described as «a tale of two navies». The former operates conventional vessels in the Gulf of Oman and the Indian Ocean; the latter concentrates in the Persian Gulf the fast boats, mines and coastal systems designed to harass rather than to win a classic naval battle.

Surface drones (USV): from concept to reality

Unmanned surface vehicles stopped being theory in Hormuz. The United States created Task Force 59 within the Fifth Fleet in 2021, specifically to integrate unmanned systems and artificial intelligence in the Gulf: it has operated platforms such as the Saildrone Explorer (autonomous surveillance sailboats) and various test USVs, according to sustained USNI News coverage. Iran, for its part, has displayed unmanned boats in parades and exercises and seized — and later released — several American Saildrones in 2022, episodes documented by specialist naval media.

The qualitative leap came with attack USVs. The war in Ukraine demonstrated in the Black Sea that explosive-laden surface drones can seriously damage a superior navy: Ukrainian attacks on Russia's Black Sea Fleet between 2022 and 2024 are the precedent every analyst cites when discussing Hormuz. Iran has fielded manned fast boats with a swarm vocation for decades; turning that concept into unmanned swarms is a technically plausible step, though the real maturity of its attack USVs is not publicly verified.

Unmanned submarines (UUV): the opaque frontier

Unmanned underwater vehicles are the area of greatest uncertainty. Iran has unveiled prototypes and claims autonomous underwater capabilities, but public evidence is thin and comes almost entirely from Iranian state media. The United States, meanwhile, is developing programmes such as Boeing's Orca XLUUV — an extra-large underwater vehicle intended, among other missions, for minelaying — whose programme has suffered documented delays.

What is well established is the traditional threat UUVs would complement: naval mines. Iran possesses an arsenal estimated at several thousand mines — contact, influence and some more sophisticated Chinese-made models — and already used them in the «tanker war» of the 1980s: the frigate USS Samuel B. Roberts nearly sank after striking an Iranian mine in 1988. Mining UUVs would make that threat more discreet and harder to attribute, but their operational Iranian deployment is unconfirmed.

Anti-ship missiles and aerial drones: the known layer

The best-documented part of the Iranian posture is land-based: coastal anti-ship missile batteries (the Noor and Qader families, derived from the Chinese C-802, and the more recent Khalij Fars, presented as an anti-ship ballistic missile), Shahed-family attack drones — the same ones Russia uses in Ukraine — and cruise missiles. The 2019 attack on Saudi Arabia's Abqaiq oil facilities, attributed to Iran by the U.S. and several European governments (Tehran denied it), showed the ability to combine drones and cruise missiles against energy infrastructure.

Could Iran close the strait?

It is the question planners and markets have asked since the 1980s. The benchmark academic analysis, Caitlin Talmadge's in «International Security» (2008), concluded that Iran could disrupt traffic for weeks or months using mines, missiles and small craft, but could not indefinitely prevent a determined coalition from reopening the passage — at the cost of a long, destructive military campaign. Twenty years on, the conclusion is still cited because the basic balance has not changed: Iran does not need to win a naval battle, only to make the risk intolerable for insurers.

Recent episodes — tanker seizures, drone attacks on merchant vessels attributed to Iran, such as the Mercer Street in 2021 — confirm the pattern: graduated pressure below the threshold of open war. Naval drones fit that strategy perfectly: they are cheap, hard to attribute and scalable.

The Western response: minehunters, escorts and the cost paradox

The flip side is the difficulty of defence. Escort operations (such as the European EMASoH/AGENOR or U.S.-led coalitions) protect specific ships but cannot cover all traffic. Minehunting is slow and minehunters are scarce and vulnerable. And there is the economic paradox that dominates drone warfare in every theatre: intercepting a $20,000 drone with a two-million-dollar missile is unsustainable, which explains the race for laser and microwave defences we have also covered in this encyclopedia.