Commercial Shipping Around Hormuz Is Increasingly Going Dark

At a Glance

• Commercial shipping through Hormuz increasingly appears to be operating under dark or EMCON conditions.
• IRGC fast craft activity expanded across both Hormuz corridors, including swarm-style formations and escort-like behavior near commercial traffic.
• Windward identified nine commercial tanker transits through Hormuz on May 11, including dark fleet-linked LPG and product tankers.
• Qatar LNG cargoes resumed transiting Hormuz for the first time since the February closure.
• Kharg Island export throughput remains constrained, with no confirmed tanker departures observed after May 7.
• Large dark tanker concentrations near Larak, Qeshm, southeastern Hormuz, and Chabahar indicate growing export staging pressure.
• U.S. forces disabled two additional Iran-linked tankers following earlier interdiction operations against M/T HASNA.
• Iran seized the sanctioned tanker JIN LI in what appears to be a strategic signaling operation.
• Piracy risk off Somalia remains elevated, with multiple hijacked vessels still positioned near the Somali coast.

Operational Overview 

Commercial shipping and maritime security activity around the Strait of Hormuz are increasingly shifting into dark or emissions-controlled conditions.

During the reporting period, Windward observed expanded IRGC fast craft activity near commercial corridors, continued dark and EMCON tanker transits through Hormuz, growing concentrations of staged dark tankers near Larak and Chabahar, and escalating U.S. interdiction activity against Iran-linked vessels.

Commercial traffic through the Strait continues despite the deteriorating environment. Windward identified multiple inbound and outbound tanker movements, including dark fleet-linked LPG and product carriers, VLCC transits toward Kharg Island, and the first successful Qatar LNG transit through Hormuz since the February closure. At the same time, vessels are increasingly displaying adaptive operating behavior, including prolonged dark anchorage periods, ship-to-ship transfers, and possible physical hull-protection measures.

Iranian export operations also appear increasingly strained. No confirmed tanker departures were observed from Kharg Island after May 7, while large dark tanker queues expanded across protected Iranian waters, suggesting Iran is buffering export capacity while managing growing bottlenecks under blockade pressure.

Taken together, the Strait is increasingly functioning as a fragmented low-visibility operating environment where military pressure, covert shipping activity, enforcement operations, and disrupted export infrastructure are becoming deeply interconnected.

IRGC Fast Craft Operations Intensify Near Commercial Traffic

IRGC-linked fast craft activity intensified across the Strait of Hormuz operating area during the reporting window. On May 7 at 07:04 UTC, imagery identified two separate clusters of high-speed small vessels moving on broadly aligned headings toward the northern corridor. The northern cluster included approximately 15–20 small fast craft, while the southern cluster included approximately 20–25 small fast craft.

Both groups displayed pronounced wake signatures consistent with speeds above 20 knots. The southern cluster was more tightly grouped and showed characteristics consistent with a coordinated swarm posture, while the northern cluster appeared more dispersed, consistent with an area patrol or screening formation. The two clusters were separated by approximately 8.7 nautical miles, confirming they were separate concurrent groups rather than the same formation observed twice.

RF collections during the same operating period showed no interceptions in the northern corridor or commercial lane, suggesting that some commercial transits may be occurring under strict emissions control conditions.

On May 8, no large IRGC fast craft formations were observed in the southern corridor, but two IRGC boats were seen crossing approximately 370 meters off the bow of a commercial vessel, possibly as a deterrence act. Two additional IRGC boats were observed heading north from the Omani Peninsula, while another two were observed heading south, likely from Iran.

By May 9, IRGC fast craft activity increased again, with five clusters of more than 80 high-speed craft observed heading north after leaving the Omani Peninsula. One inbound bulk carrier was observed transiting with a cluster of high-speed craft in formation, suggesting a possible escort or pressure posture.

Additional EO and SAR collections on May 10 and May 11 identified persistent IRGC-linked patrol behavior near the eastern Strait corridor. A cluster of 16 dark vessels ranging between approximately 20 and 70 meters was observed west of Kargan Island, with all vessels appearing stationary across multiple collections. The positioning suggests a potential new patrol or scouting zone for Iranian small craft monitoring vessels entering and exiting the Strait.

On May 11, imagery north of Larak Island identified a 180-meter oil tanker operating alongside both a high-speed craft and a dhow. Approximately one hour later, the tanker remained accompanied only by the dhow. Both smaller vessels are assessed as likely Iranian, suggesting that civilian-looking support vessels may increasingly be participating in escort, boarding, or monitoring activity alongside IRGC-linked maritime operations.

Dark Tanker Movement Through Hormuz Continues to Expand

Windward continued to identify commercial movement through the Strait of Hormuz under dark or emissions-controlled conditions. On May 8 at 13:21 UTC, EO imagery over the northern corridor identified five inbound vessels, including one crude oil tanker, one bulk carrier, one chemical tanker, one oil tanker, and one LPG tanker.

On May 9, EO imagery identified one VLCC transiting outbound through the Strait of Hormuz. Windward assesses with high confidence that the vessel loaded crude at Kharg Island no later than May 7.

Later on May 9, imagery showed six inbound transits through the Strait, including one VLCC through the southern corridor and five vessels through the northern corridor. The inbound group included two VLCCs, two bulk carriers, and two oil tankers. 

RF collections further reinforced the emissions-control pattern. On May 8, 521 RF transmissions were detected across the Strait of Hormuz area, including 84 AIS-matched. However, there were no RF emissions in the northern corridor or commercial lane during the observation window, suggesting that commercial transits may be occurring under strict EMCON conditions.

On May 11, satellite imagery identified nine commercial tanker transits through Hormuz, including six outbound and three inbound vessels. Two outbound vessels were AIS-identified dark fleet-linked operators: TARA GAS (IMO 9290270), a Panama-flagged LPG carrier operating under near-full load conditions, and a Cameroon-flagged products tanker linked to Iranian methanol trade flows.

Four additional dark outbound vessels were identified south of Larak Island alongside two bulk carriers departing Bandar Abbas, suggesting that Iranian bulk commodity and energy exports continue to operate in parallel under increasingly concealed conditions.

Inbound traffic included a VLCC assessed as heading toward Kharg Island, accompanied by a mid-range products tanker and a smaller coaster-class vessel.

Windward also observed several persistent operational patterns continuing between transit events. A Suezmax tanker flagged under Windward’s Iran risk program remained stationary near Larak for a third consecutive day while operating dark. A multi-day ship-to-ship transfer pair north of Larak also remained on station, reinforcing assessments that the corridor is increasingly functioning as both a holding zone and covert transfer area rather than solely a transit route.

Separately, Windward identified a container vessel operating with apparent stacked-container hull protection, suggesting that some commercial operators may be physically adapting vessels to the evolving missile and drone threat environment around Hormuz.

Qatar LNG Traffic Returns to Hormuz Under Controlled Transit Conditions

Qatar-linked LNG movement through the Strait of Hormuz showed a limited but significant restart. AL KHARAITIYAT (IMO 9397327) successfully transited the Strait of Hormuz on May 9 via the northern corridor, becoming the first Qatar LNG cargo to clear the Strait since Iran’s February 28 closure. The vessel is en route to Port Qasim, Pakistan, with an ETA of May 11.

The passage appears to have been enabled under the U.S.-Iran ceasefire framework mediated by Pakistan, with reported Iranian prior approval granted as a goodwill gesture. The timing indicates that the clearance was framework-driven rather than vessel-specific.

Two additional Qatar-linked LNG vessels remain idled near Qatari waters after being turned back by the IRGC on April 6, before the formal ceasefire. No updated transit clearance has been confirmed for either vessel.

All three vessels carry Windward-flagged Iran-related AIS dark activity from April to May 2026, totaling 13 incidents, though all are currently transmitting.

Iranian Expands Dark Tanker Queues as Export Pressure Builds

Windward assesses that Iranian crude export operations are under growing operational stress as dark tanker queues expand across protected Iranian territorial waters while Kharg Island throughput remains constrained.

On May 10 at 06:20 UTC, satellite imagery identified 21 commercial dark tankers operating without AIS transmission across three protected Iranian-water anchorage zones: the northern Hormuz corridor near Larak and Qeshm, southeastern Hormuz, and Chabahar east of Hormuz on the Gulf of Oman side.

Twelve of the 21 vessels were VLCC-class hulls representing an estimated combined loadable capacity of approximately 24 million barrels.

The observations coincided with the continued absence of new tanker departures from Kharg Island following May 7 and the continued expansion of the Kharg oil spill.

Within the northern Hormuz corridor, Windward identified a dark ship-to-ship transfer pair involving two tanker-class hulls. The transfer pair remained stationary across multiple observation windows, strengthening assessments that the activity represents an ongoing commodity transfer operation rather than routine bunkering behavior.

A Liberia-flagged Suezmax tanker operating under Windward’s Iran risk program also remained anchored near Larak for a third consecutive day with minimal positional drift. Imagery showed no visible hull breaches, listing, smoke, or oil sheen, indicating no visible signs of attack or casualty.

Additional dark tankers were also observed operating nearby, while IRGC-linked speedboat formations continued operating north of Larak Island in positions consistent with a protective security layer around staged export assets.

At the same time, commercial tanker traffic continued flowing inbound toward Iranian waters. Windward identified inbound Aframax crude tankers, container cargo traffic, and smaller product carriers operating within Iranian territorial waters, suggesting that Iran continues feeding crude supply toward Kharg and associated export corridors despite constrained loading throughput.

Chabahar increasingly appears to be functioning as a strategic export buffer node. On May 10, Windward identified 12 large dark tankers operating without AIS near Chabahar, including nine VLCCs and three Suezmax vessels, representing the largest single-pass concentration observed in the area during the reporting period.

The positioning is operationally significant because Chabahar sits east of the Strait of Hormuz on the Goreh-Jask pipeline outlet, allowing Iran to stage export tonnage outside portions of the Hormuz interdiction environment.

Windward assesses that the combination of protected tanker queues, continued inbound tanker flow, prolonged dark operations, and expanding IRGC maritime protection activity indicates that Iran is attempting to preserve covert export continuity while managing a significant export bottleneck centered around Kharg Island.

Iran Seizes Sanctioned Tanker 

On May 8, Iranian naval forces seized the JIN LI (IMO 9855525), previously known as OCEAN KOI, in the Gulf of Oman. The vessel is an OFAC-sanctioned 228-meter tanker linked to Iranian oil trading and owned or operated by Ocean Kudos Shipping Co Ltd.

Iranian state media claimed the vessel was attempting to disrupt Iranian oil exports, but the vessel’s profile raises questions about the intent behind the seizure. JIN LI has a long history of Iran-linked trading, ownership changes, suspected fraudulent registration, and stateless-style operations consistent with cooperation with Iranian networks.

Windward analysis found that the vessel was manipulating its reported location at the time of the event, with SAR imagery showing that its transmitted position did not correlate with its true location. 

Given its sanctions status, prior Iran-related operations, and location manipulation behavior, the seizure may function more as a deterrence or messaging act than a straightforward enforcement action.

U.S. Maritime Enforcement Activity Continues to Escalate 

On May 8, U.S. forces disabled two sanctioned Iranian tankers, SEA STAR III and SEVDA, while both vessels were transiting toward an Iranian port in the Gulf of Oman. Neither vessel was transmitting AIS at the time, and both had gone dark in April.

Both tankers had recently sailed to Malaysia, where they conducted dark activity before returning toward Iran without AIS transmissions. SEA STAR III also went dark multiple times in April in northern Iranian waters before sailing dark to the Gulf of Oman, where U.S. forces disabled it.

Together with the May 6 disabling of M/T HASNA, this brings the week’s total to three potential blockade-breaking tankers disabled by U.S. forces. All three were reportedly en route to Iranian ports, likely Chabahar.

The pattern suggests that Iranian tankers conducting dark activity in Malaysian waters and near the Strait of Malacca may provide early indicators for future blockade-breaking attempts and possible U.S. enforcement targets.

Piracy Risk Re-Emerges Along the Somali Corridor 

Piracy risk off Somalia remained elevated with multiple hijacked or seized vessels still positioned near the Somali coast.

MT EUREKA was reportedly seized around May 2 after a suspicious approach involving a green vessel and a fishing boat southwest of Yemen. Yemeni authorities reported that armed men seized the vessel and directed it toward the Gulf of Aden and Somali territorial waters.

HONOUR 25, a Palau-flagged oil products tanker hijacked on April 21, was observed approximately 2.19 nautical miles off the Somali coast. The vessel remains under pirate control after being seized approximately 30 nautical miles off Somalia while carrying an estimated 18,000 barrels of oil.

The SWARD, flagged to St. Kitts and Nevis, was hijacked on April 26 while carrying cement from Suez to Mombasa. EUNAVFOR Atalanta confirmed the vessel was pirated near Somalia’s northern coast, with 17 crew taken hostage.

The clustering of multiple hijacked vessels near Somali coastal positions reinforces the re-emergence of piracy risk across the Gulf of Aden and Somali basin during a period of broader maritime disruption.

Outlook

Commercial shipping through Hormuz increasingly appears to be operating outside traditional visibility frameworks.

AIS suppression, EMCON conditions, GPS interference, dark anchorage behavior, and covert ship-to-ship transfers continue to reduce the reliability of conventional maritime awareness across the region. At the same time, IRGC maritime activity is expanding alongside continued U.S. interdiction operations, increasing the risk of miscalculation and direct operational confrontation.

Iranian export operations also appear to be entering a more constrained phase. Kharg Island throughput remains degraded while large dark tanker concentrations near Larak, Qeshm, southeastern Hormuz, and Chabahar suggest Iran is increasingly staging crude capacity under protected holding patterns while managing export bottlenecks.

Commercial operators are simultaneously adapting both operationally and physically to the environment through prolonged dark operations, altered routing, escort behavior, and possible vessel hardening measures.

Taken together, the Strait of Hormuz is increasingly functioning as a contested low-visibility operating environment where commercial transit continues, but under growing military pressure, degraded transparency, and sustained enforcement risk.