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

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

Strategic Importance and Trade Volumes

The Strait of Hormuz, a narrow waterway connecting the Gulf to the Arabian Sea, plays a pivotal role in global energy supply. Positioned between Iran to the north and Oman, along with the United Arab Emirates (UAE), to the south, it measures approximately 50km wide at its entry and exit points, narrowing to around 33km at its most constricted section. This passage is critical for the movement of oil and liquefied natural gas (LNG), with roughly 20% of the world’s crude oil and LNG typically transiting through it. During periods of tension, the strait became a focal point for geopolitical conflict, as Iran’s actions disrupted shipping and caused a sharp rise in fuel costs.

As of early April, the U.S. and Iran had secured a temporary truce, contingent on ensuring “safe passage” through the strait. This agreement followed a period of hostilities that began on 28 February, when the U.S. and Israel launched an attack on Iran. The resulting blockage of the waterway, which is deep enough for the largest oil tankers, had a significant economic impact, with global fuel prices spiking. However, the ceasefire led to a 15% drop in oil prices, easing some of the immediate strain on markets.

Threats and Maritime Activity

During the conflict, Iran’s military capabilities—such as drones, missiles, and fast attack boats—posed a serious risk to commercial vessels navigating the strait. At its narrowest point, the waterway lies entirely within the territorial seas of Iran and Oman, extending up to 12 nautical miles from their coasts. This meant ships could be targeted without clear international boundaries. According to United Against Nuclear Iran, at least 24 commercial vessels were damaged, along with three near misses, by mid-April.

“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.

The strait also serves as a vital artery for fertiliser exports, with one-third of the world’s trade passing through it. Additionally, it is a key route for importing essential goods like food, medicines, and technology to the Middle East. Normally, around 3,000 ships traverse the waterway monthly, but this number dropped sharply during hostilities.

Regional and Global Impacts

Disruptions in the strait affected not only the Gulf states but also distant regions. China, for instance, accounted for nearly 90% of Iran’s oil exports, making it particularly vulnerable to supply interruptions. In Asia, the fuel shortage led to measures like shortened workweeks and early university closures. In Africa, South Sudan and Mauritius implemented electricity rationing, while Slovenia became the first EU nation to enforce fuel restrictions in Europe.

Historically, the strait has been a battleground. During the Iran-Iraq war in the late 1980s, strikes on oil facilities escalated into a “tanker war,” with both sides attacking neutral ships to gain economic leverage. Kuwaiti tankers transporting Iraqi oil were especially targeted. Today, the U.S. has avoided deploying warships to the strait, focusing instead on air strikes against Iranian anti-ship missile sites. Despite President Trump’s earlier call for allies and China to assist in securing the passage, his request received limited support, and he later claimed the U.S. could act independently.

Energy Dependence and Economic Significance

Many Gulf nations, including Iran, rely heavily on energy exports for economic stability. The strait’s closure during the conflict threatened their revenue streams, as well as those of international buyers. In 2025, the U.S. Energy Information Administration estimated that 20 million barrels of oil and products flowed through the strait daily, valued at nearly $600bn annually. This includes shipments from Iran, Iraq, Kuwait, Qatar, Saudi Arabia, and the UAE, with Qatar and the UAE accounting for a substantial share of LNG exports.

While the ceasefire has restored some normalcy, the strait remains a symbol of the delicate balance between energy security and geopolitical tensions. Its strategic role continues to draw attention, as any disruption could once again send shockwaves through global markets.