Three Weeks Into the Ceasefire: A Maritime Intelligence Breakdown

At a Glance

• Transit through the Strait of Hormuz increased during the third week of the ceasefire, but movement remains uneven, managed, and enforcement-driven.
• The clearest split is between visible transit through the Strait and expanding concealed activity across the wider Gulf.
• Gulf-wide vessel presence remained high, reaching 902 vessels by April 29, while dark activity surged to 170 events.
• U.S. enforcement extended beyond the Gulf with the interception of the sanctioned LPG tanker LPG SEVAN in the Arabian Sea.
• Kharg Island remains active but constrained, with loading continuing alongside dark tankers, anchorage queues, and uneven export pacing.
• Chabahar remains a key dark tanker staging zone, with five to seven dark tankers observed across the week.
• Iran-linked deceptive shipping practices intensified, including AIS spoofing off Basrah by sanctioned and falsely flagged tankers.
• Iranian crude flows to Asia declined, with no VLCC laden with Iranian crude transiting the Strait of Malacca eastbound since April 24.
• GPS jamming near Khor Fakkan and IUU fishing pressure in Oman’s EEZ added new operational risk beyond the core sanctions environment.

The Third Week of the Ceasefire at Sea

Three weeks into the ceasefire, the maritime system is showing signs of movement, but not normalization.

Transit through the Strait of Hormuz increased during the week, with 20 crossings recorded on April 29, the highest count in the reporting period. Corridor use also broadened, with seven vessels using the Southern Corridor that day. This indicates that operators are finding ways to move through the Strait under managed conditions.

But the recovery is uneven. Transit slowed after early-week gains before rising again, while Gulf-wide vessel presence remained elevated and dark activity surged toward the end of the period. The result is a split operating environment: visible transit is resuming through controlled corridors, while concealed activity is expanding around anchorages, staging zones, and alternative positioning areas.

That split defines the third week of the ceasefire. The Strait is no longer in collapse, but the broader system is still being shaped by enforcement pressure, deceptive shipping practices, and constrained Iranian export flows.

Hormuz Transit Rises, But Remains Uneven

Transit through the Strait of Hormuz fluctuated throughout the week, reflecting a controlled but unstable operating environment.

On April 25, transit rebounded to 19 crossings, including 5 inbound and 14 outbound movements, all AIS-visible. Inbound traffic consisted entirely of cargo vessels, with one flagged to Tanzania, one to Iran, and three to India. Outbound movements included three tankers flagged to Madagascar, the Caribbean Netherlands, and Panama; two bulk carriers flagged to Barbados and Iran; and nine cargo vessels, with one flagged to Gambia, one to India, one to Somalia, two to Iran, and four to Comoros.

This was followed by a slowdown on April 26, with only 8 crossings, evenly split between inbound and outbound, again with full AIS visibility. Inbound traffic included one Panama-flagged tanker and three cargo vessels, with one flagged to Comoros and two to India. Outbound movements consisted of two bulk carriers flagged to Barbados and St. Kitts and Nevis, and two cargo vessels flagged to Panama and Comoros.

On April 27, transit rose to 13 crossings, consisting of 3 inbound and 10 outbound movements. Inbound traffic included one Netherlands Caribbean-flagged tanker and two cargo vessels, one flagged to Tanzania and one to India. Outbound movements included three bulk carriers flagged to Iran, St. Kitts and Nevis, and the Marshall Islands, alongside seven cargo vessels, with one flagged to São Tomé, three to Comoros, and three to Iran. One outbound vessel operated without AIS.

On April 28, transit remained at 13 crossings, with 4 inbound and 9 outbound movements, all AIS-visible. Inbound traffic included one Panama-flagged bulk carrier and three cargo vessels, with one flagged to India and two to Comoros. Outbound movements consisted of two Panama-flagged tankers, two bulk carriers flagged to Panama and China, and five cargo vessels, with one flagged to Antigua and Barbuda, two to Iran, and two to Comoros.

By April 29, transit volume increased to 20 crossings, with 6 inbound and 14 outbound movements. Inbound traffic included two bulk carriers flagged to Panama and China, alongside four cargo vessels, with two flagged to India and two to Comoros. Outbound movements included two tankers flagged to Curaçao and Palau, two bulk carriers flagged to Iran and Panama, and ten cargo vessels, with four flagged to Iran, three to India, and three to Comoros.

The April 29 traffic pattern also showed broader corridor use, with 13 vessels routing through the Northern Corridor and 7 through the Southern Corridor. This marked the highest Southern Corridor usage observed in recent days and indicates adaptive routing as operators respond to enforcement conditions and risk exposure.

Overall, the Strait is not closed, but movement remains conditional. Operators are transiting, but behavior remains shaped by corridor selection, enforcement risk, and selective AIS visibility.

Gulf Activity Rebuilds as Dark Behavior Rises 

Gulf-wide vessel presence remained elevated throughout the week.

Vessel counts this week:

• April 25: 892 
• April 26: 920 
• April 27: 896 
• April 28: 890
• April 29: 902

Panama remained the dominant flag state throughout the period, followed by Iran, Comoros, the Marshall Islands, Liberia, and the UAE.

Dark activity showed the more significant trend this week:

• April 25: 123 
• April 26: 117 
• April 27: 111 
• April 28: 148
• April 29: 170

This indicates that increased movement is not translating into greater transparency. Instead, the system is becoming more active and more deceptive at the same time.

Blockade Impact on Dark Vessel Behavior 

Dark vessel positioning around Bandar Abbas and the Larak Island chokepoint highlights how the blockade is shifting movement patterns across the Gulf.

At Bandar Abbas, dark vessel concentration remains elevated. Multi-source intelligence shows dense clustering of tankers and bulk carriers anchored in the deepwater channel between the mainland and Qeshm Island, with additional groups along the Qeshm shoreline and extending east toward the Strait. 

This pattern is consistent across multiple collections and reflects sustained loitering rather than active transit. Vessel presence has stabilized at around 70 vessels over the past two weeks, down from approximately 90 before the blockade. Daily volumes of vessels of interest, including sanctioned, zombie, and falsely flagged vessels, continue to range between 20 and 25.

Most vessels remain at anchor rather than committing to transit, indicating sustained caution under enforcement pressure. The area continues to function as a dual-use anchorage, supporting both commercial staging and IRGC-linked activity under constrained conditions.

At the Larak Island chokepoint, the pattern is more constrained. Dark vessel detections form a narrow north-south ribbon hugging the Iranian coastline, particularly along Bandar-e Charak and the western shore of Larak Island, with minimal presence in open water. 

Between April 22 and April 27, dark transit activity through the chokepoint declined, indicating fewer non-AIS vessels moving into or out of the Arabian Gulf.

Despite this reduction, dark movement has not stopped. On April 29, three dark vessels above 200 meters, including one VLCC, were observed transiting the chokepoint, with two inbound and one outbound.

Taken together, this indicates a shift from movement to containment. Dark vessels remain present at scale, but are increasingly concentrated in controlled anchorage zones rather than actively transiting, reflecting the growing impact of enforcement on routing decisions.

U.S. Enforcement Extends Beyond the Gulf

On April 25, U.S. naval forces intercepted the sanctioned LPG tanker LPG SEVAN in the central Arabian Sea, approximately 200 nautical miles south of Pakistan.

LPG SEVAN is a Panama-flagged LPG tanker assessed as part of the Iranian dark fleet. It was designated by OFAC on April 24, one day before the interception, among 19 shadow fleet vessels linked to the transport of Iranian energy products.

The vessel had previously transported approximately 750,000 barrels of Iranian propane and butane to Bangladesh between August and November 2025. At the time of interception, it was carrying approximately 200.6 thousand barrels of LPG+/olefins, declaring Dubai as its destination. 

AIS and maneuvering data show that the vessel executed a tight 180-degree turn at approximately 11:08 UTC before resuming westbound movement. The timing and nature of the maneuver are consistent with a compelled course reversal following U.S. naval interception.

This confirms that enforcement is no longer limited to the Strait or Gulf approaches. Sanctioned vessels remain exposed across wider maritime corridors.

Kharg Island Remains Active, But Under Pressure 

Kharg Island continues to operate as Iran’s primary crude export hub, but under visible pressure.

On April 26, SAR imagery identified two tankers actively loading at Kharg Island, one VLCC and one Suezmax-class vessel, with a combined loading capacity estimated at approximately 3 million barrels. 

At least eight additional VLCCs were observed anchored south and east of Kharg, forming a substantial waiting queue.

By April 30, EO imagery detected three dark tankers drifting at Kharg anchorage, while two tankers were observed at berth at the T-jetty, including one VLCC and one oil products tanker.

This combination of loading activity, drifting dark tankers, and anchorage buildup indicates that exports are continuing, but at a controlled and uneven pace.

Chabahar Remains a Dark Tanker Staging Zone

Chabahar continued to emerge as a key eastern positioning area.

On April 26, Windward Multi-Source Intelligence confirmed the continued presence of seven dark tankers in the Chabahar anchorage area, consisting of six VLCCs and one Suezmax. ATEELA 1 (IMO 9548990), an Iran-flagged, sanctioned oil products tanker, was observed transmitting AIS in the area and assessed as a bunkering support unit for the cluster.

On April 28, Windward detected five dark tankers in the Chabahar port waiting area, with one identified with high confidence as DIONA (IMO 9569695), an Iranian-flagged VLCC assessed to have arrived from the Singapore/Malaysia ship-to-ship transfer hub, a known center for Iranian crude consolidation and redistribution.

Two AIS-transmitting Iranian-flagged vessels, the container ship KASHAN (IMO 9270696) and the bulk carrier ARTMAN (IMO 9405930), were also detected operating in proximity to the dark cluster. ARTMAN’s trading pattern, including voyages between Iran and China, aligns with profiles seen in previously intercepted vessels, reinforcing its relevance within the broader Iranian shipping network.

The dark tankers detected near Chabahar represent approximately 7–8 million barrels of carrying capacity. Their position inside Iranian territorial waters suggests deliberate staging, with vessels likely either laden and awaiting offload or in ballast awaiting loading instructions, while remaining shielded from enforcement exposure.

AIS Spoofing Around Basrah Masks Iranian Loading Patterns

Iran-linked deceptive shipping practices remain central to the operating picture.

Windward identified 10 Iran-trading, U.S.-sanctioned tankers spoofing their location to appear anchored off Basrah, Iraq. This long-standing evasion tactic allows vessels to transmit false AIS signals and voyage data indicating Iraqi destinations, while actually sailing to Iranian ports to load sanctioned crude.

The vessels identified include four VLCCs — ALICIA (IMO 9281695) and RHN (IMO 9208215), both operating under fraudulent Curacao registries, STAR FOREST (IMO 9237632) flagged to Hong Kong, and AQUA (IMO 9248473) under a fraudulent Malawi registry.

Additional vessels include the Hong Kong-flagged handysize tanker PAOLA (IMO 9299458) and the LR1 tanker ADENA (IMO 9254862), both signaling “Iraqi owner,” linked to a network identified by the U.S. Treasury as facilitating Iranian oil sales.

Three medium-range tankers — AQUALIS (IMO 9258674) under a fraudulent Guyana registry, KUSH (IMO 9282522) falsely flagged to Comoros and signaling destination “KAZ” (Khor Al Zubair), and CHARMINAR (IMO 9318022), also falsely flagged to Comoros — are part of the same pattern. CHARMINAR is linked to a known Iranian trading network.

The LPG carrier ROYAL H (IMO 9155341), flagged under a fraudulent Malawi registry and recently sanctioned, is also engaged in this activity.

Most vessels display clear spoofing indicators, including repeated positional patterns and erratic AIS trails. 

In the case of ROYAL H, voyage data simulates loading at the Iraqi LPG port of Khor Al Zubair, a known tactic among Iran-linked LPG carriers.

These tankers are part of a broader group of Iran-trading vessels now largely confined west of Hormuz under blockade pressure. Together, they illustrate how deceptive shipping practices remain central to sustaining Iranian export flows, even as enforcement tightens and physical movement becomes more constrained.

Iranian Crude Flows to Asia Decline

Iranian crude shipments reaching Asia have dropped sharply under blockade pressure.

Windward and Vortexa’s analysis shows that no VLCC laden with Iranian crude has transited the Strait of Malacca eastbound since April 24, the longest such gap since the war began. For the seven-day period ending April 27, only three VLCCs and one Suezmax entered the Strait of Malacca eastbound, all assessed as having loaded before the April 13 embargo.

U.S. forces said on April 28 that 39 vessels have been redirected under the blockade, with dozens of tankers, both laden and in ballast, confined to Iranian territorial waters, at anchor or drifting in the Gulf of Oman, or manipulating their location via AIS.

Iranian crude exports reaching Asia averaged approximately 1.3 million barrels per day during April, down from 1.9 million barrels per day loaded from Kharg in March and 2.2 million barrels per day in February.

Approximately 153 million barrels of Iranian oil remain on the water, much of it in floating storage west of Hormuz or around the Riau Archipelago, a known ship-to-ship transfer zone for Iranian crude bound for China.

One example is an Iran-flagged VLCC, which switched on AIS on April 24 as it entered the Strait. This vessel is the last VLCC laden with Iranian crude tracked in the Strait.

Limited Non-Iran Transit Continues 

An LNG carrier transited Hormuz, marking one of the few post-April 22 transits by a vessel with no apparent Iran link. The vessel was Japanese-owned, Panama-flagged, and signaling laden, showing that non-Iran-linked commercial movement remains possible, though limited.

GPS Jamming Expands Beyond Hormuz 

GPS jamming incidents also increased outside the Strait of Hormuz, particularly near Khor Fakkan, adding navigational and operational risk across key maritime approaches.

IUU Fishing Pressure Builds In Oman’s EEZ 

Over the past 12 months, 43 Chinese fishing vessels conducted 3,611 fishing operations and 338 dark activity events within Oman’s EEZ, alongside just four port visits. Notably, 33 vessels operated directly within coastal zones around Duqm and Ras Madrakah, indicating sustained activity in areas reserved for artisanal fishing.

Twelve vessels were assessed as high risk for IUU behavior, with two linked to suspected forced labor indicators. The most active vessels belong to a Chinese distant-water fleet with a documented record of fishing in protected zones, disabling AIS, and operating under false flags, including past enforcement actions.

Operations in Oman are supported by five supply tankers operating under flags of convenience — including Comoros, Gabon, Sierra Leone, and Honduras — and conducting 132 ship-to-ship transfers, enabling continuous offshore activity without port calls. This resupply model reflects a known evasion tactic and remains largely unmonitored in the region.

This level of activity, combined with similar patterns previously linked to stock depletion in other regions, indicates sustained and scalable pressure on Oman’s fisheries that warrants close monitoring.

Outlook

Three weeks into the ceasefire, the maritime system is moving more than it was a week earlier, but not under normal conditions.

Transit through Hormuz has increased, and Southern Corridor use has expanded, but access remains uneven, managed, and shaped by enforcement risk. The rebound in visible crossings does not indicate full transparency, especially as dark activity and spoofing continue to expand across the wider Gulf.

Iranian export activity remains constrained but adaptive. Kharg Island continues to load, but with queue pressure and dark tanker drift. Chabahar remains a significant staging zone. Spoofing around Basrah continues to mask Iranian loading patterns. At the same time, Iranian crude deliveries into Asia are slowing, showing that enforcement pressure is affecting downstream flow.

U.S. enforcement is also widening. The interception of LPG SEVAN in the Arabian Sea confirms that sanctioned vessels are exposed beyond the Strait and Gulf approaches, forcing operators to account for risk across broader transit corridors.

The third week of the ceasefire, therefore, shows partial movement, not recovery. The Strait is more active, but the wider system is more opaque. Visible transit is increasing, while concealed activity, enforcement reach, and regional operating risk continue to grow.