Kharg Stalls as Iran Expands Maritime Control Across Hormuz

At a Glance

• Kharg Island loading terminals were observed fully empty for the first time since April 18, despite approximately 20 staged dark tankers nearby.
• No confirmed crude departures from Kharg have been observed since May 7, reinforcing assessments of sustained export disruption.
• Dark tanker holding zones continued expanding near Larak, Qeshm, eastern Hormuz, and Chabahar.
• Persistent ship-to-ship transfer activity and prolonged dark anchorage behavior indicate growing covert staging operations inside Iranian territorial waters.
• IRGC-linked surveillance and patrol activity intensified, with hundreds of fast craft observed operating near key shipping corridors.
• Commercial vessel movement through Hormuz remained heavily restricted, with most large hulls stationary under dark or EMCON conditions.
• Windward assesses that portions of Hormuz are increasingly functioning as controlled maritime holding zones rather than normal commercial transit corridors.

Operational Overview 

The Strait of Hormuz operating environment remained heavily constrained between May 11 and May 13 as Iranian export infrastructure continued operating below normal capacity, dark tanker staging expanded across protected Iranian waters, and IRGC-linked maritime activity intensified throughout the corridor.

Kharg Island showed its clearest signs yet of sustained export disruption. For the first time since April 18, all loading terminals were observed empty despite roughly 20 dark tankers remaining staged nearby with an estimated carrying capacity exceeding 25 million barrels. No confirmed crude departures have been observed from Kharg since May 7, while imagery also identified tug and repair activity near the island’s western infrastructure, reinforcing assessments that Iran is attempting to restore damaged loading capacity while holding export tonnage in reserve.

At the same time, large concentrations of dark VLCCs, Suezmaxes, and product tankers remained stationary near Larak, Qeshm, eastern Hormuz, and Chabahar. Persistent ship-to-ship transfer activity, prolonged dark anchorage behavior, bunkering operations, and EMCON conditions reinforced indications that Iran is increasingly managing maritime flows through a layered staging and control architecture rather than normal commercial transit patterns.

Commercial movement through Hormuz continued, but under increasingly degraded visibility conditions. Limited outbound flows persisted under both AIS-transmitting and dark conditions, while RF collections repeatedly showed little to no detectable emissions activity in key commercial corridors.

Taken together, the developments indicate that significant portions of the Strait are increasingly functioning as controlled maritime operating zones shaped by covert staging, surveillance, selective transit management, and constrained export activity.

Kharg Island Shows Deepening Export Disruption

EO and SAR imagery collected between May 11 and May 13 showed no active tanker loading operations at Kharg Island for a third consecutive day.

On May 11, all loading terminals were observed empty of tankers for the first time since April 18. Despite the absence of vessels at berth, Windward identified approximately 19 staged tankers in the eastern waiting area near Kharg, including 10 VLCCs, four Aframax tankers, and five MR tankers. The combined estimated carrying capacity exceeded approximately 25 million barrels.

No confirmed crude departures have been observed from Kharg since May 7. Windward currently assesses crude export volume during the week of May 4–10 at approximately 2.68 million barrels, below the prior low-export week observed in mid-April.

Additional satellite imagery identified visible structural disruption near the southwestern Kharg terminal area. Separate collections on May 13 identified elevated tugboat and barge activity near the western terminal infrastructure, which Windward assesses may reflect ongoing repair operations associated with earlier structural damage.

At the same time, tanker queues near the island continued holding position. Approximately 20 dark tankers remained stationary in the Kharg waiting area on May 13, including eight VLCCs, two Suezmaxes, six Aframaxes, and three Panamax tankers. No large tankers in the holding area were transmitting AIS.

Windward assesses that Iran is increasingly holding export tonnage in reserve while attempting to restore loading operations and manage outbound crude flows under blockade pressure.

Dark Holding Zones Expand Across Hormuz

Large concentrations of stationary dark commercial vessels continued operating within protected Iranian territorial waters across both northern and eastern Hormuz.

EO imagery collected on May 12 over the northern Hormuz corridor identified 10 large commercial detections above 100 meters, all operating without AIS transmission. No commercial movement was detected, and no Kelvin wakes were observed, indicating the corridor fleet remained stationary.

The corridor included a persistent dark ship-to-ship transfer pair involving two tanker-class hulls measuring approximately 230 and 250 meters. The pair remained moored in the same location for a third consecutive day, reinforcing assessments that the activity represents an ongoing commodity transfer operation rather than routine bunkering.

Additional stationary vessels included a 300-meter container vessel anchored in the same southwest corridor position since May 8, alongside multiple Panamax and product tankers.

Separate EO imagery collected over eastern Hormuz identified 36 commercial vessels, of which 35 were dark and stationary near the Seerik operating area. Only one outbound crossing was observed during the collection window, involving a 79-meter dark cargo vessel heading southbound.

Windward also continued identifying dark tanker staging activity near Chabahar. EO imagery collected on May 11 identified 20 vessels, including 12 commercial vessels operating without AIS transmission, made up of five VLCCs, five Suezmaxes, one mid-sized tanker, and one general cargo vessel. The fleet remained overwhelmingly stationary, with most vessels showing minimal positional drift across multiple collections.

Windward assesses that northern Hormuz, eastern Hormuz, and Chabahar are increasingly functioning as protected holding and staging zones buffering Iranian export capacity under blockade conditions.

IRGC Maritime Surveillance Activity Intensifies 

IRGC-linked maritime surveillance and patrol activity remained elevated throughout the Strait operating area during the reporting window.

On May 11, Windward identified more than 200 fast craft operating across the broader Strait area. By May 13, approximately 342 high-speed craft were assessed operating across five monitored Hormuz sectors, significantly above the May 4–10 baseline.

The northern corridor remained the dominant operating zone, with persistent concentrations near commercial choke points and Larak Island. Multiple collections identified small IRGC-linked boats operating alongside staged commercial tankers for extended periods, behavior consistent with surveillance, escort, logistics, or security functions.

Additional imagery identified elevated dhow traffic density near the Omani Peninsula alongside clusters of Iranian-linked vessels previously associated with Iranian port visits or dark activity.

Windward continues to assess that Iran is increasingly integrating IRGC patrol craft, civilian maritime traffic, coastal logistics vessels, and small commercial craft into a layered maritime-control architecture supporting surveillance, staging, and operational sustainment across Hormuz.

Commercial Shipping Continues Under Dark EMCON Conditions

Commercial transit activity through Hormuz remained heavily degraded throughout the reporting window.

EO and SAR imagery identified limited outbound flows continuing under both AIS-transmitting and dark conditions, while RF collections repeatedly showed severe degradation in observable emissions activity across key commercial corridors.

On May 13, Windward identified several AIS-transmitting commercial transits through the Strait, including the China-flagged VLCC YUAN HUA HU (IMO 9723588), carrying Basrah crude bound for Zhoushan, China. 

In addition to YUAN HUA HU (IMO 9723588), two other vessels transmitted AIS as they transited the Strait, including the Chinese vehicle carrier XIANG JIANG KOU (IMO 9985394), and the sanctioned Cameroon-flagged LPG tanker TANIA STAR (IMO 9134165), which was observed entering.

Additional dark vessel transits were also observed operating inbound and outbound without AIS transmission.

Persistent sanctions evasion and staging activity also continued throughout the northern corridor. Multi-day bunkering operations involving a Panamax tanker and a VLCC were identified, while additional vessels remained anchored under prolonged dark conditions.

RF collections from May 12 showed no detectable emissions activity across portions of the northern commercial corridor despite visible vessel movement in EO and SAR imagery. Windward assesses this pattern as consistent with vessels operating under strict EMCON conditions.

Windward assesses that widespread AIS suppression, EMCON behavior, and dark staging activity are increasingly reducing maritime transparency across Hormuz and complicating the distinction between commercial shipping, sanctions-evasion operations, and state-supported maritime activity.

Iran Appears to Be Expanding Operational Control Over Hormuz

Regional reporting during the period reinforced indications that Iran is increasingly shifting from attempted Strait closure toward controlled access management.

According to open-source reporting on May 12, Iraq and Pakistan reached separate arrangements with Iran to secure passage for crude oil and LNG cargoes through Hormuz under Iranian oversight. Iraqi officials reportedly coordinated transit approvals directly with Tehran for VLCC movements carrying Basrah crude, while Pakistan secured separate arrangements covering Qatari LNG cargoes.

Windward assesses that the emergence of bilateral transit-clearance arrangements reinforces broader indications that Iran is increasingly attempting to formalize operational influence over vessel movement through Hormuz while preserving selective energy flows under wartime conditions.

Outlook

Kharg Island crude export throughput remains severely degraded, with no active tanker loading operations observed for multiple consecutive days despite large tanker queues remaining staged nearby. The continued absence of departures reinforces assessments that Iran is struggling to restore normal export throughput while attempting to preserve crude export continuity under blockade conditions.

At the same time, dark tanker concentrations across northern Hormuz, eastern Hormuz, and Chabahar indicate that Iran is increasingly relying on protected holding zones to buffer export capacity and manage outbound flows. Persistent ship-to-ship transfer activity, bunkering operations, and prolonged dark anchorage behavior reinforce indications that covert cargo-transfer and sanctions evasion operations are expanding inside Iranian territorial waters.

Commercial shipping activity through Hormuz also remains heavily constrained. Widespread EMCON behavior, AIS suppression, and limited visible large-hull movement continue across both inbound and outbound traffic flows, while IRGC-linked surveillance and patrol activity remains elevated near critical choke points and commercial corridors.

Windward assesses that the Strait of Hormuz is increasingly operating less as a conventional commercial shipping corridor and more as a controlled maritime operating environment shaped by surveillance, staging, selective transit management, and constrained export logistics.