The War at Sea: How Iran's Blockade of the Strait of Hormuz Is Choking the World's Oil Supply

Since February 28, 2026, the narrow waterway connecting the Persian Gulf to the open ocean has become the most dangerous shipping lane on Earth. Iran's Islamic Revolutionary Guard Corps has attacked commercial vessels with drones, missiles, and explosive-laden boats, declared the Strait of Hormuz closed to all traffic, and created a cascading energy crisis that is now rippling across every continent.

The attacks are escalating. On March 12, six vessels were struck in a single day — the worst yet — including two oil tankers set ablaze in Iraqi waters that killed at least one crew member [1]. With tanker transits through the strait down 99% from pre-crisis levels, roughly 750 ships trapped in the waterway, and oil prices breaching $100 per barrel, the world is confronting its most severe energy supply disruption since the 1973 Arab oil embargo [2].

Origins of the Crisis

The maritime crisis is inseparable from the broader military conflict. On February 28, 2026, the United States and Israel launched joint strikes against Iran that included the killing of Supreme Leader Ali Khamenei [3]. Iran's retaliatory response was sweeping: missile and drone attacks on U.S. military bases, strikes on Israeli territory, and attacks on Gulf state allies. But Iran's most consequential move was at sea.

On March 2, a senior IRGC official formally confirmed that the Strait of Hormuz was closed to all vessel traffic, threatening any ship that attempted passage [3]. The declaration transformed a military conflict into a global economic crisis overnight. Approximately 20% of the world's daily oil supply and significant volumes of liquefied natural gas normally transit the 21-mile-wide chokepoint between Iran and Oman [4].

The effect was immediate. Major container shipping companies — Maersk, CMA CGM, and Hapag-Lloyd — suspended all transits through the strait and related routes including the Red Sea [3]. Tanker traffic plummeted by 70% within days, then collapsed to near zero. Over 150 ships anchored outside the strait rather than risk passage [2].

A Growing Toll on Ships and Crews

Iran's IRGC has systematically targeted commercial vessels that ignored its closure warnings, attacking ships of multiple nationalities with an expanding arsenal of weapons.

March 1: The first oil tanker attacked in the Strait of Hormuz, reported by Omani authorities [5].

March 6: A tugboat dispatched to assist the damaged vessel Safeen Prestige was struck by two missiles and sank, leaving at least three crew members missing [6].

March 7: The IRGC claimed drone strikes on the oil tanker Prima in the Persian Gulf and the U.S.-linked oil tanker Louise P in the Strait of Hormuz [3].

March 11: The crisis intensified sharply. The IRGC announced strikes on two commercial vessels — the Thailand-flagged Mayuree Naree and the Liberia-flagged Express Room — claiming both ships had "ignored alerts and warnings from the IRGC Navy" [7]. Twenty crew members of the Mayuree Naree were rescued by the Royal Navy of Oman after the vessel caught fire, but three crew members remained trapped aboard [8]. The Japan-flagged container ship ONE Majesty sustained damage from an unknown projectile, and the MV Star Gwyenth was hit off the UAE coast [6].

March 12: The attacks widened beyond the strait itself. Explosive-laden Iranian drone boats struck two fuel tankers — the Marshall Islands-flagged Safesea Vishnu and Malta-flagged Zefyros — in Iraqi waters near the Port of Basra, setting both ablaze and killing at least one crew member [1]. Iraq's State Organization for Marketing of Oil shut down all oil port operations in response [9]. Separately, Al Jazeera reported six vessels attacked in a single day, amid reports of Iranian drone boats and sea mines [10].

By March 12, at least a dozen commercial vessels had been damaged or destroyed — flagged to the United States, Thailand, Japan, Liberia, Marshall Islands, Malta, and the UAE, among others.

Source: FRED / U.S. Energy Information Administration

Data as of Mar 11, 2026CSV

Oil Markets in Turmoil

The price of crude oil tells the story of this crisis in a single line. WTI crude, which was trading near $67 per barrel on February 27, surged to $94.65 by March 9 — a 41% increase in less than two weeks [11]. Brent crude followed a similar trajectory, with prices reaching as high as $126 per barrel at their peak on March 8, crossing the $100 mark for the first time in four years [12].

On March 12, Brent crude traded at $100.50 per barrel — up 9.26% in a single session — after Iran's new supreme leader, Mojtaba Khamenei, declared that the Strait of Hormuz must remain closed as leverage against the United States [12]. An IRGC military spokesperson warned oil prices could reach $200 per barrel [2].

Source: FRED / U.S. Energy Information Administration

Data as of Mar 11, 2026CSV

The EIA has radically revised its forecasts. The agency now projects Brent crude to average $79 per barrel for 2026, a sharp increase from its previous forecast of $58 per barrel issued just one month earlier [13]. Goldman Sachs raised its Q4 Brent forecast amid expectations of a prolonged disruption [14].

The IEA's Record Response — and Its Limits

Facing the most severe oil supply disruption in its 52-year history, the International Energy Agency on March 11 announced that its 32 member countries would release 400 million barrels of crude from strategic reserves — the largest coordinated drawdown ever, dwarfing the 182 million barrels released after Russia's invasion of Ukraine [15].

But analysts quickly noted the math doesn't work. The 400-million-barrel release is roughly equal to four days of global production — or about 16 days of the crude volume that normally transits through the Gulf [16]. With the strait effectively closed, the net supply loss amounts to approximately 15 million barrels per day of crude and refined products. The IEA drawdown can offset only a fraction of that shortfall.

"Markets are underestimating the disruption to global energy markets," analysts warned, noting the crisis could last months rather than weeks [16]. Interior Secretary Doug Burgum called for the release, framing it as a necessary but insufficient stopgap [17].

Diplomatic Fallout

The attacks on ships flying flags of neutral nations have generated international condemnation beyond the immediate belligerents.

Thailand responded forcefully after the IRGC struck the Mayuree Naree on March 11. On March 12, Deputy Permanent Secretary for Foreign Affairs Sirilak Niyom summoned Iranian Ambassador Nassereddin Heidari and demanded a formal apology [8]. Thai Prime Minister Paetongtarn Shinawatra publicly denounced the attack as "not appropriate," while authorities raced to rescue the three missing crew members [18]. The Iranian ambassador expressed condolences and pledged to convey Thailand's protest to Tehran [8].

The broadening of attacks to Iraqi waters on March 12 raised particular alarm. Iraq — not a party to the conflict — saw its oil export operations paralyzed after the tanker attacks near Basra [9]. The incident underscored that Iran's maritime campaign was no longer confined to the Strait of Hormuz itself but extending across the entire Persian Gulf.

The Escort Question

As attacks escalated, calls grew for naval escorts to reopen the strait. President Trump and energy officials signaled readiness to have the U.S. Navy escort tankers, with the Pentagon drawing up plans under the name "Operation Epic Escort" [19].

But the reality is more complicated than the rhetoric. A senior administration official acknowledged on March 12 that the U.S. military is "not ready" to accompany oil ships through the Strait of Hormuz, estimating that a full escort system would not be operational "until the end of March, or perhaps even the beginning of April" [20].

The challenge is immense. Newsweek described the task of reopening the Strait of Hormuz as the U.S. Navy's "complicated challenge," noting the threat of Iranian mines, drone boats, anti-ship missiles, and fast attack craft operating from nearby Iranian territory [21]. The International Crisis Group flagged the strait as one of the most dangerous flashpoints in the broader conflict [22].

Pakistan, meanwhile, has independently launched naval escort operations for merchant shipping, as the maritime security threat spreads beyond the immediate Hormuz chokepoint into the wider Arabian Sea [19]. A shadow fleet of tankers has been observed dominating the few remaining Hormuz crossings, with Iran ramping up bypass loading operations [23].

Source: GDELT Project

Data as of Mar 12, 2026CSV

A Crisis Without Precedent

The scale of this disruption has few historical parallels. During the 1980s "Tanker War" between Iran and Iraq, some 546 vessels were attacked over eight years. The current crisis has seen more than a dozen ships hit in under two weeks.

The 1973 Arab oil embargo, which triggered a global recession, involved a deliberate production cut but left shipping lanes open. Today, the physical closure of the world's most important oil chokepoint — combined with active military strikes on commercial vessels — represents a more fundamental threat to the infrastructure of global energy trade.

The economic consequences extend far beyond oil. LNG shipments to Asia have been severely disrupted. Container shipping rates have spiked across routes touching the Middle East. Insurance premiums for Gulf transits have become, in many cases, prohibitively expensive — effectively reinforcing the blockade even for vessels willing to take the risk [4].

What Comes Next

Three critical variables will determine whether this crisis deepens or stabilizes.

First, Iran's new supreme leader, Mojtaba Khamenei — who assumed power after his father's killing — has explicitly stated that the Hormuz closure should be used as leverage in negotiations [12]. This suggests the blockade is a deliberate strategic tool, not a temporary escalation, and may persist as long as the broader military conflict continues.

Second, the timeline for naval escorts remains uncertain. Even once operational, escorting tankers through a narrow strait under threat from shore-based missiles, mines, and drone boats is an enormously complex military operation that could itself trigger further escalation.

Third, the IEA's strategic reserves provide a buffer — but a finite one. If the crisis extends into April and beyond, as many analysts expect, the 400-million-barrel release will be exhausted, and global markets will face the full weight of the supply disruption.

For now, the Strait of Hormuz remains effectively closed, oil prices continue to climb, and the ships that once carried a fifth of the world's energy sit idle — trapped, anchored, or ablaze.