Washington and Tehran agreed terms to end their months-long conflict and reopen the Strait of Hormuz by June 15, 2026, Reuters reported — closing out one of the most consequential episodes of maritime disruption in the postwar era.

The closure had been building since late February. Iran began blocking shipping traffic through the strait on February 28, 2026, and by March 4, Iranian forces had declared it formally closed and begun attacking vessels attempting transit. The effective zero-transit threshold was crossed on March 16, when not a single commercial ship passed through the chokepoint in a 24-hour period, according to Brookings. The proximate trigger was a U.S.-Israeli military campaign against Iran; the strait became the primary lever Tehran pulled in response.

The Scale of the Disruption

The numbers are stark. By April 21, the International Maritime Organization had logged roughly 20,000 mariners and 2,000 vessels stranded in the Persian Gulf, according to Wikipedia's crisis summary. Even weeks later, when some movement resumed, the throughput remained negligible: as of early May, only four commercial vessels transited in a 24-hour period — two eastbound, two westbound — Anadolu Agency reported. Pre-crisis, the strait typically handles roughly 20% of global oil trade and a fifth of the world's LNG flows. That context makes the near-standstill — which NBC News was still describing as ongoing as recently as June 3 — a supply shock with few modern precedents.

The closest historical parallel is the Iran-Iraq War of 1980–1988, when the tanker war phase made transit genuinely hazardous and produced sustained shipping disruptions — AP flagged that episode as context in March. The difference this time was the completeness of the closure: not merely dangerous passage, but effectively no passage at all for a sustained period.

Market and Diplomatic Fallout

Saudi Aramco CEO Amin warned in May that disruption to oil exports via the strait could push the market's recovery timeline out to 2027, Reuters reported. India, one of the world's largest crude importers, pivoted to Latin American and African suppliers to compensate for interrupted Gulf flows, per a separate Reuters report from May 25.

On the diplomatic track, Washington proposed a UN Security Council resolution in early May to defend freedom of navigation and formally put on record Iran's attempt to "hold the world's economy hostage," according to the U.S. State Department. Tehran, for its part, ran a parallel public-legal strategy: Iranian MFA consulates published position papers in late May arguing that the new arrangements in the strait were legally justified under doctrines of aggression response and fundamental change of circumstances, with Tehran's Geneva mission framing the closure as a matter of sovereign prerogative rather than breach of international law.

Iran's Persian Gulf Strait Authority had declared the waterway closed until further notice, per Crisis Group's June 11 update — even as Iran's Ministry of Foreign Affairs had claimed in March that no disruption had occurred, a position the observable vessel data made untenable. The dual messaging — legal maximalism externally, denial domestically — was consistent with Tehran's posture during previous confrontations.

What the Deal Changes

The June 15 interim peace agreement ends active hostilities and commits both sides to reopening the strait. What it does not resolve, at least in the public record, is the underlying architecture: the terms of passage, any Iranian conditions on vessel nationality or cargo type, and the enforcement mechanism if either party walks back commitments.

Iran's stated position through the crisis was that the "only viable solution" was a permanent end to war, lifting of any maritime blockade, and restoration of normal passage. Whether the June 15 deal satisfies those conditions in Tehran's own reading — or whether it is treated as a temporary arrangement subject to renegotiation — will determine how quickly tanker operators and their insurers actually send vessels back through the 33-nautical-mile-wide bottleneck.

War-risk insurance premiums for Persian Gulf transits will be the first observable signal. Shipowners will not commit laden VLCCs to the route until underwriters price the risk at commercially operable levels. After months of near-zero traffic, that repricing takes time — and Aramco's warning about a 2027 oil-market recovery timeline reflected precisely that lag.

The strait is nominally open again. The question the market is now pricing is how fully, and how durably.