April 28, 2026: Iran War Maritime Intelligence Daily

At a Glance

• Hormuz transit holds at 13 crossings, with 10 outbound and 3 inbound movements.
• Gulf vessel presence declines to 896, indicating a contraction in activity.
• Dark activity falls to 111 events, continuing a downward trend.
• Iranian crude flows to Asia drop sharply, with no new VLCC arrivals since April 24.
• Approximately 153 million barrels remain on water, concentrated in regional storage zones.
• Piracy risk off Somalia escalates, with multiple vessel hijackings and active pirate groups.

Operational Overview 

Maritime activity across the Strait of Hormuz and surrounding corridors remains constrained but operational, with moderate transit levels and continued reductions in both vessel count and dark activity.

On April 27, transit volumes held at a moderate level following prior fluctuations, while Gulf-wide vessel presence declined, indicating a partial contraction in overall activity. At the same time, dark activity continued to decrease, pointing to a short-term reduction in deceptive shipping practices alongside lower traffic levels.

Beyond the Gulf, external pressure on Iranian export flows is becoming more visible. Shipments toward Asia have declined sharply, while vessels remain concentrated within regional waters or along alternative routing corridors.

Across the system, vessel behavior reflects a controlled but restricted environment, where movement continues under enforcement pressure and broader logistical constraints.

Transit Levels Hold Under Constraints

Transit activity through the Strait of Hormuz remained steady on April 27, but below earlier peaks.

A total of 13 vessels crossed the Strait, consisting of 3 inbound and 10 outbound transits. Of these, 12 were AIS-visible, with one outbound vessel operating without AIS.

Inbound traffic included one tanker flagged to the Netherlands Caribbean and two cargo vessels flagged to Tanzania and India. Routing was split between corridors, with the tanker and one cargo vessel transiting via the Northern Corridor, while a smaller Indian dhow transited via the Southern Corridor.

Outbound traffic was led by a mix of bulk carriers and cargo vessels. This included three bulk carriers flagged to Iran, St. Kitts and Nevis, and the Marshall Islands, alongside seven cargo vessels flagged to São Tomé, Comoros (3), and Iran (3). One outbound vessel conducted transit without AIS.

Transit remains active, but volumes continue to reflect operational constraints rather than a return to stable flow.

Gulf Activity Contracts

Total vessel presence across the Gulf declined to 896 vessels, a decrease of 24 compared to the previous day.

Panama remains the dominant flag state with 142 vessels, followed by Iran (96), Comoros (89), the Marshall Islands (75), the UAE (70), and Liberia (66).

Fleet composition includes 149 bulk carriers, 134 product tankers, 80 crude tankers, 66 container ships, 41 LNG and LPG carriers, and 34 chemical tankers.

Dark activity events declined further to 111, continuing the downward trend observed in recent days.

The simultaneous drop in vessel count and dark activity indicates a contraction in overall maritime activity, rather than a fundamental shift away from deceptive shipping practices.

Iranian Crude Flows to Asia Drop Under Blockade Pressure

The U.S. blockade has more than halved Iranian crude shipments reaching Asia over the past 10 days, with further declines expected into May. This is one of the clearest indicators to date of pressure on Iran’s shipping logistics chain, which supports oil flows worth billions of dollars to the Iranian regime.

No VLCC laden with Iranian crude has been tracked sailing through the Strait of Malacca since April 24, the longest gap since the war began. The chokepoint provides rare visibility into Iranian tanker movements because vessels must broadcast AIS and draft while entering and leaving the busy waterway.

For many Iran-linked dark fleet tankers, this is often the first visible signal since loading crude off Kharg Island, Iran’s key export port. Most tankers sail with AIS off before and after this brief window. Not broadcasting a vessel’s position via AIS is a deceptive shipping practice long used by Iran’s dark fleet and contravenes international maritime regulations.

AIS signals from Iran-loading dark fleet tankers tracked by Windward show that, for the seven-day period ending April 27, only three VLCCs and one Suezmax entered the Strait of Malacca eastbound. All appear to have loaded before the April 13 embargo was imposed by U.S. forces on vessels sailing to or from Iranian ports.

According to Vortexa, none of the seven tankers that were identified loading crude or condensates in Iran since April 13 have completed the 12-day voyage across the Gulf of Oman and Indian Ocean and sailed through the Strait of Malacca.

U.S. forces said on April 25 that 37 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.

Yesterday, M/V Sevan was among 19 “shadow fleet” vessels sanctioned by the U.S. Department of Treasury for activities related to transporting billions of dollars worth of Iranian energy, oil and gas products, including propane and butane, to foreign markets.

Earlier today, Sevan… pic.twitter.com/7HdJ5iHNF7

— U.S. Central Command (@CENTCOM) April 25, 2026

Windward intelligence shows that Iranian crude exports reaching Asia via the Strait averaged 1.3 million barrels per day during the first 28 days of April. That is well below the 1.9 million barrels per day loaded from Kharg Island in March, and broadly aligned with the 1.2 million barrels per day seen loading so far in April, according to Vortexa. In February, before the war began, Vortexa recorded Iranian loadings at 2.2 million barrels per day.

At the same time, approximately 153 million barrels of Iranian oil remain on the water. Much of this volume is held in floating storage west of Hormuz or on vessels that sailed to the Riau Archipelago, in Malaysia’s EEZ.

The Riau area has long been used for ship-to-ship transfers of Iranian crude, enabling onward movement to China, Iran’s largest buyer. Many Iran-linked tankers that transit the Strait of Malacca move to this area, switch off AIS while transferring cargo to another tanker, and reappear only when sailing outbound through the Strait.

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.

LNG Transit Signals Limited Non-Iran Movement

An LNG carrier transited Hormuz today, marking one of the few post-April 22 transits by a vessel with no apparent Iran link since the two container ship attacks.

The vessel is Japanese-owned and Panama-flagged, and its signaling indicates it is laden. 

Its successful transit shows that non-Iran-linked commercial movement remains possible, but still limited and closely shaped by the elevated risk environment.

Hijackings Signal Escalation in Somalia Piracy Risk

Piracy risk off Somalia has been upgraded to “substantial” following a series of hijackings and attempted attacks over the past week.

On April 26, a cargo vessel was redirected by unauthorized individuals to a position approximately 6 nautical miles northeast of Garacad. AIS data shows the vessel anchored in the area on April 27, marking the third piracy incident in five days.

This follows the hijacking of a Somalia-flagged fishing vessel on April 21 and the seizure of the Palau-flagged oil products tanker Honour 25 (IMO 1099735) days later. The tanker is now signaling from a port roughly 145 nautical miles north of the cargo vessel, confirming both vessels are being held near Somali ports.

Additional incidents earlier in the quarter reinforce the trend. Two piracy events were reported in Q1, including the hijacking of an Iranian-flagged fishing dhow approximately 400 nautical miles east of Mogadishu. That vessel was abandoned in early April under pressure from European naval forces.

Both the tanker and cargo vessel currently under pirate control had prior operational links to Somalia and were assessed as high risk, with patterns tied to smuggling or sanctions-evasion activity. Smaller vessels regularly transiting Somali waters remain the most exposed targets.

A Joint Maritime Centre update on April 26 confirmed that a Pirate Action Group is active in the Somali basin, with threat levels raised from “moderate” to “substantial.” Seasonal inter-monsoon conditions between March and April are also contributing to increased pirate activity.

Taken together, these developments indicate a re-emerging and coordinated piracy threat across key Indian Ocean routes, adding a new layer of risk beyond the Gulf.

Outlook

Transit through the Strait remains active but constrained, with moderate volumes and limited dark activity reflecting a tightly managed operating environment. The decline in Gulf-wide vessel presence points to a short-term contraction rather than stabilization, as operators continue adjusting to enforcement pressure and uncertainty.

At the same time, Iranian crude flows toward Asia are increasingly disrupted. Cargo continues to be loaded and held on water, but fewer shipments are completing long-range delivery, leading to growing concentrations in regional storage zones and alternative routing areas.

Beyond the Gulf, rising piracy activity off Somalia is adding external pressure to already-strained maritime routes. The combination of constrained transit, reduced export reach, localized vessel accumulation, and expanding security threats continues to define an operating environment where movement is possible, but increasingly complex and risk-driven.