The Strait of Hormuz has long been vulnerable to geopolitics, but it has moved to the center of the latest Iran conflict as the U.S. and Israel’s war with Iran thrust the waterway back into the crosshairs. Nearly all traffic has ground to a halt in the strait that connects the Persian Gulf with the world’s oceans, leaving a critical route for oil and other energy-linked cargo largely inactive.
The disruption is being driven by risk to commercial shipping, including attacks on vessels and threats of further strikes. The stoppage of nearly all tankers carrying oil, gas and other goods through the passage has also translated into supply cutbacks by some of the world’s largest producers, because their crude has struggled to move.
The current wave is now in its third week, with the broader conflict shaping market outcomes beyond the water itself. Roughly a fifth of the world’s oil traveled through the Strait of Hormuz before the war, and strains on supply have sent fuel prices soaring, according to the Associated Press reporting. As covered earlier by MSI, crude oil prices have shown volatility as the Hormuz disruption has expanded; the latest developments add to that pressure MSI previously reported on these swings.
Despite the near-halt in traffic, dozens of vessels have still managed to cross the strait, according to maritime and trade data platforms cited by the Associated Press. The persistence of some movement has meant the risk has not produced a total shutdown, but it has still constrained capacity enough to affect trading behavior and destination flows.
Part of why the strait remains a recurring focus is its geographic and legal character. While Iran and Oman have territory in the Strait of Hormuz, the narrow shipping channels are viewed as international waters that all ships can use. Even so, Tehran’s influence—bolstered by its nearby military presence and its control of key islands in the area—has repeatedly shaped how safe commercial traffic feels to operators and insurers.
The Associated Press also outlined past episodes in which the strait faced disruption or threats of closure. During the Iran-Iraq “Tanker War” of the 1980s, both sides attacked tankers and other vessels in and near the strait, using naval mines to shut down traffic at specific points. The U.S. became involved in the conflict as well, including a one-day battle in 1988 and, later, the shooting down of an Iranian commercial airliner it mistook for a fighter jet, killing 290 people, the report said.
In that episode, the strait did not close completely. U.S. ships escorted Kuwaiti oil tankers to protect them against Iranian attacks, but the passage still became extremely dangerous, and shipping disruptions followed. In later years, similar pressure emerged through threats tied to sanctions and nuclear disputes.
At the end of 2011 and into 2012, Iran threatened to close the Strait of Hormuz in response to sanctions over its nuclear program, as Western measures targeted Iranian energy and financial channels. While the threats did not lead to a full closure, the resulting turbulence and supply shifts contributed to oil-price swings, with Brent trading above $100 in December 2011 and for much of 2012 before peaking at more than $126 a barrel in March 2012.
Threats also resurfaced after the U.S. withdrew from an Obama-era nuclear accord with Iran in May 2018. With sanctions restored and pressure raised over Iranian oil exports, then-Iranian President Hassan Rouhani repeated threats to close the strait, but Iran did not ultimately shut it down. Brent ended 2018 near $54 a barrel, according to the Associated Press reporting.
From 2019 through 2025, the Associated Press report described a pattern of attacks and seizures. The U.S. blamed Iran for limpet mine attacks on vessels near the strait in 2019 and for a fatal drone attack on an Israeli-linked oil tanker in 2021, which Tehran denied. Separate from attacks, Iran seized vessels it alleged were smuggling fuel, including a Portuguese-flagged cargo ship in 2024 and Greek tankers held for months in 2022, among other seizures—while the strait remained open.
The Associated Press said fears about closure also increased during a June 2025 Israel-Iran war that lasted 12 days, particularly after the U.S. entered with bombings on three Iranian nuclear and military sites. Yet, the report said Iran did not close the strait and oil did not see lasting price surges; despite early price jumps, Brent finished below $67 a barrel by the war’s end, the report said.