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The United States began enforcing a naval blockade of all Iranian ports on Monday, adding a new layer of disruption to the Strait of Hormuz at a moment when roughly 800 merchant vessels remain stranded in and around the Persian Gulf and Brent Crude has surged past $100 per barrel.
The blockade took effect at 10 a.m. Eastern Time on April 13, hours after weekend negotiations between Washington and Tehran in Islamabad ended without a deal. U.S. Central Command (CENTCOM) specified that the measures would be enforced against vessels of all nations entering or departing Iranian ports and coastal areas, including those on the Arabian Gulf and Gulf of Oman, but would not impede ships transiting the strait to and from ports not linked to Iran.
The distinction may offer little comfort to the global shipping industry. No tanker transits were observed after the blockade began. The oil tanker Rich Starry, loaded with Iranian crude and bound for China, made a dramatic reversal rather than attempting an exit, joining a stationary flotilla of approximately 800 vessels, including 400 oil and gas tankers, most of which have been idle since late February.
A Chokepoint Under Dual Siege
The strait, which normally carries about 20% of the world’s seaborne oil and liquefied natural gas, has been effectively shut since February 28, when the United States and Israel launched coordinated military strikes against Iran. Iran’s Islamic Revolutionary Guard Corps (IRGC) responded by closing the waterway, launching confirmed attacks on at least 21 merchant ships and reportedly laying sea mines in the passage.
Tanker traffic collapsed by roughly 70% in the opening days and never recovered. Only 21 tankers have transited the route since the war began, compared with more than 100 ships daily before the conflict.
A two-week ceasefire announced on April 8 raised hopes of a reopening, but those expectations faded quickly. Sultan Ahmed Al Jaber, CEO of Abu Dhabi National Oil Company (ADNOC), said bluntly that the strait was not open, describing Iran’s conditions for passage as coercion rather than freedom of navigation. He noted that 230 loaded oil tankers were waiting inside the Gulf.
Iran had begun charging transit tolls reported at up to $2 million per vessel, a move that drew sharp condemnation from Washington and prompted the blockade announcement. An Iranian army statement on Monday warned that if the security of Iran’s ports is threatened, no port in the Persian Gulf or Arabian Sea would be safe.
Shipping Giants Stay on the Sidelines
Major container lines continue to keep their distance. Maersk said the ceasefire may create transit opportunities but does not yet provide full maritime certainty, adding that any decision to send ships through Hormuz would depend on continuous risk assessments. The carrier has been operating a land bridge system through ports in Jeddah, Salalah, Sohar, and Khor Fakkan to move cargo into the Gulf region by road.
Hapag Lloyd CEO Rolf Habben Jansen told customers that resuming normal network operations would take at least six to eight weeks even under favorable conditions, estimating additional weekly costs of $50 million to $60 million from the crisis. He noted that roughly 1,000 merchant ships remain stuck in the Persian Gulf, including six Hapag Lloyd vessels carrying a combined 25,000 standard containers.
Analysts have estimated that more than 250,000 TEU of containerized cargo is stranded across the region. MSC has invoked 19th century general average provisions and begun offloading containers at available safe ports, charging customers $800 per box plus retrieval costs.
Energy Markets Flash Red
Brent Crude futures jumped 8% to around $103 per barrel on Monday following the blockade announcement, recouping losses from the previous week. U.S. crude rose to $104.24 per barrel in early trading.
The physical market is even tighter. The spot price of dated Brent, the benchmark for actual cargo deliveries, had already climbed to $131.97 per barrel last Thursday, reflecting acute scarcity of real barrels despite the ceasefire. Amrita Sen, founder of Energy Aspects, described the logistics situation as a complete mess, noting that Middle East producers have shut down 13 million barrels per day of production because tanker traffic has collapsed.
Goldman Sachs warned that if the strait remains mostly closed for another month, Brent could average above $100 per barrel for the entirety of 2026, with prices potentially reaching $120 in the third quarter under a prolonged disruption scenario.
What Comes Next
Even a full reopening would not bring quick relief. Peter Tirschwell, vice president for maritime and trade at S&P Global Market Intelligence, pointed to a critical imbalance: roughly 100 container ships are waiting to exit the Gulf, but virtually none are waiting to enter. Empty tankers need to sail back in to reload, a process analysts say could stretch through July before oil flows normalize.
France has announced preparations for a multinational mission aimed at restoring freedom of navigation through the strait, with a conference to be convened alongside the United Kingdom in the coming days. Reports on Tuesday indicated that Washington and Tehran may be considering a further round of talks before the original two-week ceasefire window closes on April 22.
For now, the world’s most critical energy chokepoint remains caught between two competing blockades, and every day that transit stays restricted, the costs compound across shipping, energy, food, and fertilizer supply chains worldwide.
