Why the Strait of Hormuz Matters in the Iran War

A temporary halt to hostilities between Iran and the United States was announced, contingent on ensuring “safe passage” through the Strait of Hormuz. This vital waterway, which Iran had effectively closed since the US and Israel launched an attack on 28 February, serves as a critical artery for global energy trade. Approximately 20% of the world’s oil and liquefied natural gas (LNG) typically traverses the strait, and the conflict had led to a sharp rise in fuel prices worldwide.

Following the ceasefire agreement, global oil prices dropped by roughly 15% within days. The strait, measuring around 50km in width at its entrances and narrowing to 33km at its most constricted point, separates the Gulf from the Arabian Sea. Its depth accommodates the largest crude oil tankers, making it essential for Middle Eastern producers and consumers alike.

According to the US Energy Information Administration (EIA), over 20 million barrels of oil and related products pass through the strait daily in 2025. This equates to nearly £447bn in annual energy trade. While Iran contributes significantly, other Gulf states such as Iraq, Kuwait, Qatar, Saudi Arabia, and the UAE also rely on this route. Additionally, about one-third of global fertilizer trade moves through the strait, often linked to Middle Eastern natural gas production.

During the recent tensions, ship traffic through the strait plummeted. The US government reported that in 2024, Qatar exported 9.3 billion cubic feet per day (Bcf/d) of LNG via the waterway, while the UAE accounted for 0.7 Bcf/d. Liquefied Natural Gas (LNG) is created by cooling natural gas to a liquid state, reducing its volume by 600 times, and then reconverted at destination for residential and industrial use.

Strategic Vulnerability and Threats

The strait lies entirely within Iran and Oman’s territorial waters at its narrowest point, governed by United Nations rules that permit control up to 12 nautical miles from coastlines. During the conflict, Iranian drones, missiles, fast attack boats, and potential mines posed a significant risk to vessels navigating the route. By 2 April, at least 24 commercial ships had been targeted, with three near misses, according to United Against Nuclear Iran.

“You can be attacked, and you can’t get insurance or it is extremely expensive,” said Arne Lohmann Rasmussen, chief analyst at Global Risk Management, during the period of instability.

Regions dependent on Middle Eastern energy exports faced severe consequences. Asia, in particular, was hit hard, with China alone accounting for 90% of Iran’s global oil sales. The fuel crisis disrupted daily life, prompting governments to implement measures like remote work, shortened workweeks, and early university closures. In Africa, South Sudan and Mauritius introduced electricity rationing, while Slovenia became the first EU nation to enforce fuel restrictions in Europe.

US Military Response

The US has not stationed warships in the strait, focusing its military actions on air strikes against Iranian targets. On 18 March, US forces bombed anti-ship missile sites along the waterway. Former President Trump had previously urged allies and China to secure Hormuz with naval presence, but his appeal received limited support. He later claimed the US could manage the situation independently, citing its past use of military force to restore maritime flow during the 1980s Iran-Iraq war.