Scouring Strait of Hormuz for mines could take weeks, delaying return to normal shipping

What Happened

A preliminary US–Iran deal to end the war and reopen the Strait of Hormuz faces a prolonged delay as the waterway remains mined, according to shipping and security sources. Minesweeping operations—using conventional minesweepers and underwater drones—could take 40 to 50 days before insurers and shipping companies deem the passage safe, potentially stranding tens of millions of barrels of oil in the Gulf. Iran’s National Defense Council previously warned of mining access routes, and US Secretary of State Marco Rubio told a Senate hearing on June 2 that Iran had 'mined large segments of Hormuz, international waters.' Germany’s navy, citing US and UK intelligence, reported mines at four unverified locations. Oman’s Maritime Security Center warned of a suspected floating mine on May 30. The US military’s Central Command confirmed ongoing efforts to clear sea mines laid by Iran’s Islamic Revolutionary Guard Corps, while Iran has not directly confirmed any mine-laying. Shipping traffic through the strait remains at a fraction of pre-war levels, rising to 12–15 vessels per day from the normal 120–140.

Key Actors

Why It Matters

The Strait of Hormuz handles 20% of the world’s daily oil and LNG supply, and the mine threat—even after a ceasefire—underscores Iran’s enduring asymmetric leverage. Global oil stockpiles are already at their lowest since 2003, and a weeks-long delay in reopening the strait would tighten energy markets further. The extensive mine-laying campaign reflects Iran’s strategy to assert control over the waterway and complicate post-war normalization, potentially prolonging the economic and security fallout for Gulf exporters and global consumers.

Watch For

Concrete implementation of the US–Iran ceasefire and strait-opening deal; deployment of the European minesweeping mission (Macron said it could be active within two to three days of the deal being finalized); duration and findings of clearance operations, with industry estimates of 40–50 days or longer; any public release of minefield locations by navies or Oman; and decisions by war-risk underwriters, tanker operators, and major shipping lines to resume transits, likely signaled by insurance guidance and BIMCO advisories.