At a Glance
- Kharg Island exports fall to ~3M barrels, well below the ~8M weekly average.
- IRGC attacks and seizure of vessels on April 22 raise the total incidents to 34.
- Transit remains unstable, with activity fluctuating sharply between April 20 and 22.
- Bandar Abbas shows heavy congestion, with the majority of vessels operating without AIS.
- A cluster of 8 large tankers forms near Chabahar, representing ~14M barrels of capacity.
- Dark activity remains elevated despite temporary declines in parts of the Gulf.
- Vessel behavior reflects adaptation to enforcement, not a halt in maritime flows.
Operational Overview
Maritime dynamics across the Strait of Hormuz and surrounding corridors continue to shift from constrained activity toward selective escalation, with enforcement, evasion, and direct engagement shaping vessel behavior.
Iranian crude exports from Kharg Island declined sharply during the week of April 13–19, with total volumes estimated at approximately 3 million barrels, significantly below the year-over-year weekly average of around 8 million barrels. Satellite imagery confirms a mid-week pause in loading activity, followed by a limited resumption, indicating disruption to primary export operations.
At the same time, activity is redistributing rather than stopping. Large tanker clusters have formed east of Hormuz near Chabahar, while congestion and dark activity remain elevated near Bandar Abbas. These patterns point to adaptation under pressure rather than a breakdown in flows.
Operational risk escalated again on April 22, when IRGC forces attacked three outbound container vessels and seized at least one. This marks an escalation to direct vessel interdiction and signals a shift toward more aggressive maritime control tactics.
The operating environment is defined by suppressed transit, increased reliance on dark operations, and continued probing of enforcement boundaries.
Kharg Island Exports Show Clear Disruption
Kharg Island recorded its lowest weekly crude export volume since the war began.
Between April 13 and 19, total departures are estimated at approximately 3 million barrels, significantly below the typical weekly average of around 8 million barrels. EO imagery from April 18 shows no active loading at the terminals, a rare pause not observed since the start of the conflict.
Loading activity partially resumed by April 20, with SAR imagery confirming a single large tanker, likely a VLCC, loading at the eastern terminal, assessed at approximately 2 million barrels.
Three confirmed departures occurred during the week, including two VLCCs, each loaded with approximately 2.01 million barrels and departed on April 15 for China, and a Suezmax, which loaded approximately 1.09 million barrels and departed on April 16 for China.
Despite these movements, the overall cleared volume remains significantly reduced. This suggests either a temporary operational slowdown or early signs of sustained disruption to Kharg’s export capability.
Bandar Abbas Remains Congested and Opaque
Vessel density and non-cooperative behavior remain high around Bandar Abbas and Shahid Rajai.
Windward detected 296 vessels in the area on April 21, with only 74 transmitting AIS. The AIS-visible fleet is dominated by Iranian-flagged vessels clustered around the Bandar Abbas anchorage.
The remaining vessels include a significant number of large AIS-dark detections, with the top 30 ranging from 322 meters down to approximately 140 meters. This distribution is consistent with a mix of VLCCs, tankers, and large cargo vessels operating without signal transparency.
Notably, ship-to-ship activity was detected west and north of Larak Island, involving two dark VLCCs and two oil tankers. This reinforces the continued use of offshore transfer operations within Iranian-controlled staging zones.
Transit Activity Remains Volatile
Transit patterns between April 20 and 22 highlight continued instability rather than recovery.
April 20
Transit activity rebounded following the previous day’s suppressed movement.
Fifteen vessels crossed the Strait, with six inbound and nine outbound. Inbound traffic included two tankers flagged to Panama and Iran, alongside four cargo vessels flagged to Togo, Comoros, and two to Iran, with one operating without AIS. Outbound traffic consisted of two tankers flagged to Comoros and Botswana, and seven cargo vessels flagged to Gambia, two to Comoros, and four to Iran, with one vessel operating without AIS.
Gulf-wide vessel presence declined to 816 vessels, reflecting continued clearing of previously stalled traffic. Panama remained the leading flag state with 133 vessels, followed by Iran (79), Comoros (75), Marshall Islands (70), Liberia (68), and the UAE (58). Fleet composition included 157 bulk carriers, 137 product tankers, 69 crude tankers, 58 container ships, 42 LNG and LPG carriers, and 35 chemical tankers.
Dark activity fell to 120 events, marking the first meaningful decline since the blockade began.
April 21
Transit activity dropped to its lowest level of the month.
Only seven vessels crossed the Strait, one inbound and six outbound. The inbound was a Mali-flagged tanker, while the outbound traffic consisted of one Panama-flagged container vessel and five cargo vessels — one flagged to Panama, one to Comoros, and three flagged to Iran — all but one operating without AIS.
Gulf-wide vessel presence declined to 760 vessels, reflecting continued drawdown following earlier disruptions. Panama remained the dominant flag with 135 vessels, followed by the Marshall Islands (69), Comoros (68), Liberia (66), the UAE (63), and Iran (52). Fleet composition included 143 bulk carriers, 118 product tankers, 81 crude tankers, 53 container ships, 40 LNG and LPG carriers, and 32 chemical tankers.
Dark activity remained elevated, with 117 events recorded.
April 22
Activity partially rebounded, but remained unstable.
Nine vessels crossed the Strait — six inbound and three outbound. Inbound traffic included two tankers flagged to Mali and the Bahamas, and three cargo vessels flagged to Liberia, Cameroon, and India, and one other vessel transited, which was flagged to Comoros. Outbound traffic consisted of one Panama-flagged LPG tanker, one Panama-flagged container vessel, and one Marshall Islands-flagged bulk carrier, all operating with AIS.
Gulf-wide vessel presence increased to 868 vessels, indicating a partial rebuild following the previous day’s low. Panama remained the leading flag with 139 vessels, followed by Comoros (85), Iran (84), Marshall Islands (73), Liberia (70), and the UAE (69). Fleet composition included 154 bulk carriers, 135 product tankers, 83 crude tankers, 65 container ships, 40 LNG and LPG carriers, and 33 chemical tankers.
Dark activity rose to 132 events, signaling a renewed increase in deceptive shipping behavior.
These fluctuations reflect a system driven by short-term risk signals rather than stable operating conditions.
IRGC Attacks Signal Escalation
April 22 marked a renewed escalation in direct maritime engagement, with coordinated attacks against outbound commercial vessels transiting the Strait of Hormuz.
Three outbound container vessels were targeted within a narrow operational window, all while transiting with AIS switched off and resuming transmission in or near the attack zone.
MSC FRANCESCA (IMO 9401116), a Panama-flagged container vessel, was fired upon at approximately 04:55 UTC around 15 nautical miles northeast of Oman while transiting outbound from Saudi Arabia. The vessel was engaged by an IRGC gunboat without prior VHF challenge, sustaining damage to the hull and accommodation. It was subsequently seized and escorted into Iranian territorial waters, where it remains at anchor. No injuries or pollution were reported.
EPAMINONDAS (IMO 9153862), a Liberia-flagged container vessel departing the UAE, was engaged shortly after at approximately 05:00 UTC around 8 nautical miles west of Iran. The vessel was fired upon with small arms and RPGs, again without prior warning. Initial reports indicated bridge damage, later assessed as minor. Iranian authorities claimed the vessel was seized, though this has been disputed by Greek officials. The crew was reported safe.
EUPHORIA (IMO 9235828), a Panama-flagged container vessel, was also fired upon in the same operational window while transiting outbound toward Jeddah. The vessel had been operating without AIS prior to the incident and resumed transmission shortly after. No significant damage or casualties were reported, and the vessel successfully cleared the Strait into the Gulf of Oman.
The attacks occurred without prior VHF challenge or standard communication protocols and demonstrate coordinated use of kinetic force against commercial shipping. This marks a shift from recent stand-off engagements toward direct vessel seizure and control, representing a clear escalation in IRGC maritime tactics.
Since February 28, the total number of vessels struck or fired upon has risen to 34, reinforcing a sustained and escalating threat environment for vessels transiting the Strait.
Tanker Cluster Forms East for Hormuz
A large cluster of dark tankers has formed east of Hormuz near Chabahar, reflecting a significant shift in vessel positioning under sustained enforcement pressure.
Windward Multi-Source Intelligence identified seven VLCCs on April 19, along with a separate ship-to-ship transfer involving two smaller tankers, roughly 100 meters each, all operating without AIS. By April 22, imagery confirmed six VLCCs and one Suezmax in the same area, all operating without AIS and remaining idle at anchorage. Imagery from April 23 showed that all vessels remained in the exact same positions, with one additional tanker, possibly another Suezmax, joining the cluster, bringing the total to six VLCCs and two Suezmax vessels.
None of the vessels are positioned at berth or engaged in active loading, and no ongoing ship-to-ship transfer configuration is observed. At full capacity, this cluster represents approximately 14 million barrels of potential crude transport capacity.
A supporting case reinforces this pattern. The sanctioned tanker AMAK, operating under a fraudulent flag of Madagascar, and with a history of Kharg loadings, declared a destination of Iraq but failed twice to enter the Gulf on April 17 and 18, reversing course both times. The vessel is now drifting in Pakistan’s EEZ, unable or unwilling to proceed, indicating direct deterrence rather than logistical delay.
Taken together, these patterns indicate that the Chabahar cluster most likely represents ballast tankers unable to enter the Gulf due to enforcement pressure. The sustained dark posture, identical stationary positioning over multiple days, and absence of loading or transfer activity all support the assessment that these vessels are waiting rather than actively operating.
This suggests that the U.S. blockade is effectively constraining primary export corridors from the Arabian Gulf, forcing tanker accumulation outside the enforcement zone. At the same time, the persistence and gradual growth of the cluster indicate deliberate positioning, with vessels likely preparing for rapid re-entry or alternative routing once conditions allow.
Outlook
The Strait of Hormuz remains unstable, with vessel behavior driven by a combination of enforcement pressure, direct engagement, and uncertainty around access.
Export activity from Kharg has declined sharply, but flows have not stopped. Instead, activity is shifting geographically and operationally, with vessels repositioning east of Hormuz and relying more heavily on dark operations and offshore mechanisms.
At the same time, the escalation in IRGC tactics, including direct attacks and vessel seizures, is increasing the immediate risk to commercial shipping and further suppressing transit confidence.
The accumulation of tankers near Chabahar suggests that enforcement is constraining traditional export corridors while creating new pressure points outside the Gulf. These vessels are not idle by default, but positioned for rapid movement once conditions allow.
The operating environment is defined by instability and adaptation, where enforcement continues to expand, evasion strategies evolve, and maritime flows persist under increasingly constrained and volatile conditions.
