Strait of Hormuz Ship Attacks Surge in September, Tanker Traffic Collapses

The Strait of Hormuz and the wider Persian Gulf went through one of their most violent months for commercial shipping in September 2026. After a period of relative calm in direct fighting during August, the United States and Iran resumed strikes at the very end of the month, and the confrontation has increasingly moved to sea. Tankers, gas carriers and cargo vessels are now caught between Iranian attacks on ships using routes that Tehran does not authorize, US strikes on Iranian oil tankers and a US naval blockade of Iranian ports that remains in force.

The new wave of attacks began on 31 August. The Saudi-flagged very large crude carrier Sidr was hit by unknown projectiles roughly 16.6 nautical miles northeast of Khasab, Oman, while trying to enter the Gulf through the southern corridor of the strait. Minutes later, the Liberia-flagged supertanker Senegal Prosperity was struck by three projectiles about 17 nautical miles east of Khasab. The ship lost communications and was left listing, with damage to its engine room and ballast tanks. No casualties were reported in either attack.

Hostilities escalated quickly in the first days of September. On 1 September, US forces hit Iranian air defense sites, radar systems and maritime assets, and Tehran answered with missiles and drones fired at targets across the region. Local officials said one US strike hit a home hosting a wedding, killing five people. On 5 September, the Islamic Revolutionary Guard Corps (IRGC) launched two ballistic missiles at two US Navy warships patrolling near the strait. Neither ship was hit, but US Central Command (CENTCOM) retaliated by striking three Iranian oil tankers, including one near Kharg Island, the heart of Iran's crude export system, and the tanker Kylo in the Gulf of Oman. The next day, Iran claimed it had hit an unmanned US vessel trying to enter the strait, a claim Washington did not confirm.

The violence then spread beyond the strait itself. On 9 September, a Panama-flagged supertanker holding about 1.84 million barrels of oil in floating storage near Iraq's Basrah Oil Terminal was struck in an attack that maritime intelligence analysts attributed to Iran. Late on 12 September, Iranian state media reported that an Iranian commercial vessel had been hit near Qeshm Island, about 14 miles from the port of Bandar Abbas, leaving one person dead and four injured. Local Iranian officials blamed an unnamed enemy, and the US did not comment on the incident.

The same weekend, the Panama-flagged tanker El Gaia, which CENTCOM said had already been disabled by an Iranian missile in August, was hit again by a drone while drifting off Oman. The IRGC claimed the ship had struck a naval mine while using what it called an unauthorized route, an account CENTCOM dismissed as false. Oman's Maritime Security Center said the attack took place about 103 nautical miles northeast of Musandam and that a Royal Navy of Oman vessel evacuated 23 crew members. Two seafarers are still missing, and the tanker was towed to an Omani port once the engine-room fire had been brought under control. On 14 September, another vessel was reportedly hit by an unknown projectile in the strait, without damage or casualties.

Attacks continued at a steady pace during the second half of the month. During the night of 17 to 18 September, an oil tanker caught fire after being struck by an unidentified projectile in the strait, only hours after Iran said its forces had targeted a ship that was trying to cross the waterway illegally. All crew members were reported safe. On 20 September, the Liberia-flagged LPG carrier Al Maryah, operated by ADNOC, was hit by debris from unknown projectiles during an outbound transit. It suffered no major damage and its 19 crew members were safe when it anchored at Khor Fakkan in the United Arab Emirates. On 21 September, the UK-flagged, Greek-owned crude tanker LR Stephanie was struck by an unknown projectile while sailing inbound through the southern corridor. Two crew members sustained minor injuries, and the tanker continued under its own power toward Jebel Ali.

Iran asserts sovereignty over the strait and wants shipowners to pay transit tolls to its Persian Gulf Strait Authority, which has blacklisted 77 vessels for using the southern corridor along the Omani coast or for crossing without paying. Most of the merchant ships hit this month were using that southern route, where the US military has been offering navigation guidance to some commercial tankers.

The impact on traffic is visible. According to Kpler data, only 17 commodity vessels crossed the strait over the weekend of 19 and 20 September, down from 37 a week earlier, compared with about 125 large commercial vessels per day before the war started on 28 February. On 22 September, maritime analytics firm Windward counted just 12 transits and no outbound movement at all through the southern corridor, which suggests a pause after the attacks of 20 and 21 September. Many Gulf producers keep exporting on tankers sailing with their transponders switched off or through ship-to-ship transfers off Fujairah, but the risk has pushed charter rates for supertankers leaving the Gulf above 1 million dollars per day, a record for the route.

Pressure on the strait also increased because of events in the Red Sea. Houthi drone attacks forced Saudi Aramco to shut its East-West pipeline on 13 September, which halted crude loadings at the Red Sea port of Yanbu. Saudi Arabia responded by sending more crude through Hormuz, and around 14 million barrels were loaded on seven supertankers inside the Gulf on 20 September. Sources said the pipeline restarted on 22 September, which could allow exports from Yanbu to resume and ease part of this dependence.

Overall, the situation has deteriorated since the start of September. Direct military exchanges between the US and Iran have resumed, attacks have spread from the strait to Iraqi waters and to Iranian vessels, at least one person has been killed at sea and two seafarers are missing, and visible traffic has fallen sharply. As of 23 September, no agreement has been announced, and shipowners and insurers continue to treat the Strait of Hormuz as one of the most dangerous waterways in the world.