Why the Strait of Hormuz matters so much in the Iran war

Why the Strait of Hormuz Matters So Much in the Iran War

The United States and Iran reached a ceasefire agreement, contingent on ensuring “safe passage” through the strategic waterway known as the Strait of Hormuz. This narrow passage, which had been effectively closed by Iran since the attacks by the US and Israel on 28 February, is a critical artery for global energy trade. During the period of tension, the strait’s blockade caused a sharp rise in fuel prices worldwide.

Geographical and Strategic Significance

Bounded by Iran to the north and Oman, along with the United Arab Emirates (UAE), to the south, the Strait of Hormuz is a 50km-wide corridor at its entrances, narrowing to just 33km in width. This chokepoint links the Persian Gulf to the Arabian Sea and is deep enough to accommodate the largest crude oil tankers. It serves as a vital route for Middle Eastern oil and liquefied natural gas (LNG) producers, as well as their international buyers.

In 2025, the strait was expected to handle approximately 20 million barrels of oil and related products daily, according to the US Energy Information Administration (EIA). This translates to nearly $600bn in annual energy trade. The oil originates from multiple Gulf nations, including Iraq, Kuwait, Qatar, Saudi Arabia, and the UAE. Qatar, in particular, accounts for a large portion of global LNG shipments through the strait, alongside the UAE.

Impact of Disruption

With around 20% of the world’s LNG also passing through the strait, the economic consequences of the conflict were severe. In 2024, Qatar exported about 9.3 billion cubic feet per day (Bcf/d) of LNG, while the UAE contributed 0.7 Bcf/d. Additionally, the strait is essential for fertiliser exports, with roughly one-third of global trade moving through it. It also facilitates the import of food, medicine, and technology to the Middle East.

During the hostilities, ship traffic through the strait dropped significantly. Typically, about 3,000 vessels pass through monthly, but this number dwindled as Iran threatened to target tankers and other ships. The United Nations allows countries to control up to 12 nautical miles of their territorial seas, and at the strait’s narrowest point, all shipping lanes fall within Iranian and Omani waters.

Threats and Consequences

“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 crisis.

The Iranian military posed a major risk to maritime traffic, employing drones, missiles, fast attack boats, and potentially mines. As of 1 April, the non-profit United Against Nuclear Iran reported that at least 24 commercial vessels had been struck, with three more suffering near misses. The disruptions have affected economies across Asia, with China alone accounting for about 90% of Iran’s oil exports to the global market.

The fuel shortage has disrupted daily life in Asia, prompting governments to implement measures such as remote work, shortened workweeks, and early university closures. In Africa, South Sudan and Mauritius introduced electricity consumption limits, while Slovenia became the first EU country to enforce fuel rationing.

US Military Response

The US has not deployed warships to the strait, opting instead for air strikes on Iranian targets. On 18 March, US forces targeted anti-ship cruise missile sites along the strait. President Trump had previously urged allies and China to secure the waterway with naval presence, but his call received limited support. He later asserted that the US could manage the situation independently.

Historically, the US has used military force to restore maritime flow through the strait. During the Iran-Iraq war in the late 1980s, strikes on oil facilities led to a “tanker war,” where both nations attacked neutral ships to exert economic pressure. Kuwaiti tankers transporting Iraqi oil were especially at risk during this period.