How a Months-Long Blockade of a Global Oil Chokepoint Finally Ended

Washington and Tehran agreed on June 15, 2026, to end their conflict and reopen the Strait of Hormuz, Reuters reported. The closure had strangled one of the world's most critical shipping lanes for months.

Iran began blocking the strait on February 28, 2026, and by March 4, Iranian forces formally closed it to traffic and started attacking ships trying to pass through. By March 16, not a single commercial vessel had crossed the chokepoint in 24 hours — a threshold that had never been reached in the modern era, according to Brookings. The blockade was Tehran's main response to a U.S.-Israeli military campaign against Iran.

Why This Matters to Oil Prices and Shipping

The Strait of Hormuz is a narrow waterway between Iran and Oman that carries roughly one-fifth of the world's oil and a similar share of liquefied natural gas (LNG — natural gas chilled into liquid form for transport). Before the crisis, it was one of the busiest shipping corridors on Earth.

The closure paralyzed maritime trade. By late April, the International Maritime Organization had documented roughly 20,000 sailors and 2,000 vessels stranded in the Persian Gulf, according to Wikipedia's crisis summary. Even when some movement resumed weeks later, the throughput was tiny: by early May, only four commercial vessels were transiting per day — two heading east, two heading west — Anadolu Agency reported.

To understand the scale: before the crisis, roughly 20 or more vessels would normally pass through each day. The near-total halt was a supply shock — a sudden, unplanned reduction in available goods — without recent parallel. The closest historical comparison is the Iran-Iraq War of 1980 to 1988, when tanker traffic faced genuine physical danger and suffered major disruptions, AP noted. But even that episode allowed some ships through. This time was different: almost nothing moved.

What Happened to Oil Markets and Trade

The blockade rippled outward fast. Saudi Aramco's CEO warned in May that the disruption could delay oil market recovery until 2027, Reuters reported. Major oil importers scrambled to find alternatives. India, one of the world's largest crude buyers, began sourcing oil from Latin America and Africa instead of the Persian Gulf to offset the lost shipments, according to a separate Reuters report from May 25.

Diplomatically, the two sides squared off. In early May, Washington introduced a UN Security Council resolution to defend freedom of navigation and formally accuse Iran of trying to "hold the world's economy hostage," the U.S. State Department said. Iran responded with its own legal argument: position papers from Iranian foreign ministry consulates in late May claimed the closure was justified under international law as a response to aggression and changing circumstances. Tehran's stance — that closing the strait was a matter of national sovereignty, not a breach of international rules — was clearly at odds with observable reality. By late May, Iran's Persian Gulf Strait Authority maintained the waterway was closed indefinitely, Crisis Group reported on June 11, while Iran's foreign ministry continued denying any disruption had occurred at all.

The Deal Ends Hostilities, but Questions Remain

The June 15 agreement halts active conflict and commits both countries to reopening the strait. What it does not clarify — at least publicly — is the finer architecture of resumption. The deal does not appear to settle whether Iran will impose conditions on which ships can pass, which cargo types are allowed, or how violations will be enforced if either side breaks the agreement.

The real test will come in the shipping market itself. Tanker operators will not risk expensive ships and cargo through the strait until war-risk insurance premiums — the extra cost of insuring voyages in dangerous zones — fall to levels that make commercial sense. That repricing happens slowly after months of near-zero traffic. Aramco's estimate of a 2027 recovery timeline reflected exactly this lag: physical reopening of the strait is one thing; confidence that it will stay open is another.

The corridor is nominally passable again. Whether vessels actually move through it — and whether they keep moving — depends on how durable the peace actually turns out to be.