March 25, 2026: Iran War Maritime Intelligence Daily

At a Glance

• Strait of Hormuz transit remains highly constrained, with only four AIS-visible crossings and no activity in standard commercial lanes.
• Transit continues through a controlled northern corridor, with vessels staged and sequenced for passage.
• Iran has formalized its selective transit model, allowing “non-hostile” vessels to pass under coordination.
• Iranian crude exports remain steady, but are increasingly supported by declining floating storage rather than new supply.
• Dark activity persists, with 318 events recorded and vessels entering the Gulf without AIS transmission.
• A dual fertilizer supply shock is emerging in East Sub-Saharan Africa due to disrupted Gulf flows and reduced South Asian production.
• Port disruptions are intensifying outside the Gulf, with acute transshipment pressure in Oman.
• Maritime security risk remains elevated, with 20 vessels attacked and sustained military deployment across the region.
• Russian export infrastructure remains under pressure, with Primorsk offline and Ust-Luga only partially recovered.

Operational Overview 

Maritime activity in and around the Strait of Hormuz remains constrained but operational under a clearly selective transit framework. While commercial shipping has not resumed through standard lanes, vessel movements continue through controlled routing patterns aligned with Iranian oversight.

On March 24, only four AIS-transmitting vessels crossed the Strait, while standard commercial lanes remained empty as of 02:15 GMT. At the same time, vessel presence across the Gulf remained substantial, indicating that operations have not stopped, but are being filtered and managed.

Iran’s control model is now explicit. Its communication to the UN and IMO that “non-hostile” vessels may transit if coordinated reinforces what is already visible in routing behavior. Transit is no longer governed by open navigation, but by conditional access.

Beyond the Strait, the broader maritime system is adjusting. Energy flows remain active, but underlying structures are shifting, and second-order impacts are emerging across global commodity markets.

Strait of Hormuz Transit and Control

Transit activity through Hormuz remains limited and tightly structured.

On March 24, one AIS-transmitting vessel exited the Gulf, while three entered. Movements followed the established northern routing pattern near Larak Island, reinforcing the emergence of a managed corridor rather than open passage.

At the same time, two cargo vessels above 50 meters entered the Gulf without transmitting AIS while hugging the Omani coastline. This indicates continued reliance on reduced-visibility movement alongside controlled transit.

As of 02:15 GMT, no vessels were observed in standard commercial lanes, while at least 10 vessels above 180 meters were positioned north of Larak Island, likely awaiting sequencing for controlled passage.

This pattern suggests that transit is not only restricted but actively staged and regulated.

Gulf Vessel Presence Overview

AIS-transmitting foreign vessel activity in the Arabian Gulf totaled 592 vessels, including 325 cargo vessels and 267 tankers.

Breakdown by vessel subclass:

• Bulk carriers: 149 vessels.
• LNG and LPG carriers: 37 vessels.
• Oil products tankers: 71 vessels.
• Crude oil tankers: 67 vessels.
• Container vessels: 38 vessels.
• Other vessel types: 230 vessels.

Top flag registries (excluding Gulf states):

• Panama: 124 vessels.
• Liberia: 78 vessels.
• Saint Kitts and Nevis: 25 vessels.
• Singapore: 24 vessels.
• India: 19 vessels.
• Malta: 17 vessels.
• Barbados: 17 vessels.
• Hong Kong: 17 vessels.

Top company locations by vessel presence:

• Marshall Islands: 112 vessels.
• Greece: 81 vessels.
• China: 76 vessels.
• Singapore: 50 vessels.
• Liberia: 54 vessels.

Despite constrained transit through Hormuz, global participation in Gulf operations remains intact, reflecting continued commercial engagement under elevated risk.

Vessel Activity Trends

Operational behavior continues to shift in response to the evolving risk environment.

The data shows continued movement alongside reduced anchoring and persistent deceptive behavior, indicating adaptation to constrained operating conditions.

Iranian Crude Export Activity and Floating Storage

Iranian crude exports remain relatively steady, but the structure supporting them is changing.

As of March 23, approximately 163 million barrels of Iranian oil were on the water, with more than 90% bound for China. Total floating volumes stand at approximately 182.8 million barrels, including 165 million barrels of crude, 11.4 million barrels of clean petroleum products, and 6.4 million barrels of dirty petroleum products.

Floating storage has declined by approximately 40 million barrels since January 1, while in-transit volumes have increased by roughly 50 million barrels. Total cargo remains stable at 140–160 million barrels, indicating that exports are being sustained by drawing down reserves rather than increasing supply.

Operational signals support continued activity, with at least seven VLCC ship-to-ship transfers identified in the EOPL hub near Malaysia and Singapore on March 23. In addition, 129 tankers linked to Iranian crude are currently sailing dark.

In addition, an Iran-flagged, OFAC-sanctioned tanker ceased AIS transmission on March 16, after signaling Assaluyeh as its destination on March 15, and has remained dark since. SAR imagery from March 23 confirms multiple vessels in the Assaluyeh area, including three at oil terminals, consistent with active loading operations.

The sanctioned tanker is assessed to have loaded approximately 370.3 thousand barrels of South Pars condensate, departing on March 24 with a reported destination of Nanjing, China, reinforcing continued condensate export flows despite AIS suppression.

If current trends persist, floating storage could be depleted by mid-May, introducing a vulnerability to export continuity.

East Africa Fertilizer Supply Shock

A dual supply disruption is emerging for East Sub-Saharan Africa.

Out of 224 bulk carriers currently trapped in the Gulf, 22 serve the Gulf-to-East Africa fertilizer route. Since March 1, 19 of those vessels, or 86%, of these vessels have stopped sailing to East Africa, implying a lane-specific shortfall of roughly 1.6 million metric tons per year relative to pre-crisis flows.

At the same time, Qatar’s LNG force majeure has forced fertilizer production cuts in Pakistan and Bangladesh, removing a key secondary supply source.

The result is a compounded disruption, with both primary and backup supply channels constrained.

Port Operations Disruptions

Port activity reflects increasing reliance on rerouting and transshipment hubs.

Inside the Gulf

Jebel Ali, UAE:

• 8 transshipment rollovers (+33.33% from the previous day, +211.11% compared with the 7-day average).
• 5 transshipment-delay cases (−50% from the previous day, +20.69% compared with the 7-day average).
• 35 port-of-destination changes (+29.63% from the previous day, +308.33% compared with the 7-day average).
• 3 transshipment-changed cases (0-baseline from the previous day, +200% compared with the 7-day average).

Outside the Gulf

Salalah, Oman:

• 5 port-of-loading rollovers (+150% from the previous day, +400% compared with the 7-day average).
• 93 transshipment rollovers (0-baseline from the previous day, +1062.5% compared with the 7-day average).
• 55 transshipment-delay cases (+1733.33% from the previous day, +203.15% compared with the 7-day average).
• 12 port-of-destination changes (−66.67% from the previous day, +10.53% compared with the 7-day average).

These patterns indicate that disruption is being redistributed across the network, with external hubs absorbing displaced flows and experiencing rising congestion.

Military and Security Environment

The regional security environment remains highly elevated, with:

• 20 vessels have been attacked or targeted since the start of the conflict.
• 10 energy and port infrastructure sites have been hit.
• 114 military and law enforcement vessels are deployed across the Gulf, including 69 firefighting vessels.

Operational patterns show clustering around incident locations, suggesting ongoing response activity and potentially unreported events.

Iran’s formal position on coordinated transit reinforces the selective-access model already in place.

Russian Oil and Infrastructure Disruption

Russian export infrastructure remains under pressure following Ukrainian strikes.

Primorsk remains offline, with ongoing fire activity and confirmed damage to multiple storage tanks, while Ust-Luga has resumed limited operations but recorded no exports on March 24. Remote Sensing Intelligence shows severe damage to 4-6 oil tanks at Primorsk, while Ust-Luge shows no active fires. 

Despite continued oil volumes in circulation, infrastructure vulnerability is increasing, introducing forward risk to export continuity.

Chinese Undersea Mapping Activity 

Chinese maritime survey operations continue to display patterns consistent with dual-use undersea mapping.

The research vessel DONG FANG HONG 3 (IMO 9801110) has conducted extensive survey operations across the South China Sea, Philippine Sea, Northwest Pacific, and Indian Ocean between March 2024 and March 2026. Its operational pattern includes seven dark activity periods totaling 155.9 hours, concentrated near Hainan Island military facilities and deep-ocean zones critical to submarine warfare.

Analysis identifies four additional Chinese research vessels with similar profiles operating in parallel. Their deployment patterns indicate a systematic, state-directed undersea mapping program with clear military relevance for submarine navigation, detection, concealment, and broader oceanographic surveillance.

The coordinated nature of these operations suggests mission alignment beyond purely civilian scientific research.

Outlook

The maritime system remains active but increasingly defined by control, constraint, and redistribution.

Transit through Hormuz is not resuming to normal conditions, but continuing under a selective, permission-based model. Iranian exports remain stable for now, but are increasingly dependent on finite floating storage. Secondary impacts, including commodity supply disruptions and port congestion, are expanding beyond the region.

If current dynamics persist, maritime operations will remain constrained but functional. However, continued pressure on infrastructure, supply buffers, and security conditions introduces growing fragility into the system.

The trajectory will depend on whether controlled transit can be sustained, or whether additional escalation shifts the system toward broader disruption.