Week Four of the Iran War: A Maritime Intelligence Breakdown

At a Glance

• Hormuz is no longer operating as an open transit chokepoint, but as a controlled, permission-based corridor with selective access and emerging denial patterns.
• Gulf vessel presence remains high, but movement is constrained, staged, and increasingly dependent on clearance and rerouting decisions.
• Iranian exports remain stable and prioritized, with China deepening dependence across both crude and LPG flows.
• Russian oil continues to move at scale, despite growing infrastructure vulnerability following targeted strikes.
• Oman has become the central logistics workaround, absorbing rerouted cargo, fuel demand, and shifting energy flows under rising security exposure.
• Port systems are absorbing disruption at scale, with rerouting, congestion, and destination changes now embedded in operations.
• Energy markets are fragmenting, with disruptions across LPG, jet fuel, and fertilizer supply chains extending impact beyond the region.
• Enforcement and security risks are expanding across multiple theaters, from European interdictions to Black Sea strikes and Red Sea escalation signals.

The Fourth Week of the Iran War at Sea

Four weeks into the conflict, maritime activity is no longer defined by disruption alone, but by the emergence of a new operating model.

The system has not stopped. It has adapted.

The Strait of Hormuz is functioning under controlled access rather than open navigation. The Gulf remains active, but movement is constrained and uneven. Energy flows continue, but through alternative routing, selective permissions, and shifting dependencies. At the same time, rerouting has scaled beyond short-term adjustments, forming new logistics corridors centered around Oman and the Red Sea.

What is emerging is not a temporary disruption, but a reconfiguration of how maritime trade operates under sustained geopolitical pressure. Access, routing, visibility, and even compliance are being redefined in real time.

This week marks a transition point. The system is no longer reacting to disruption. It is reorganizing around it.

Hormuz Under Control and Increasingly Filtered 

Transit through the Strait of Hormuz over the past week remains significantly below normal levels, as movement is no longer governed by open commercial navigation, but by Iranian control. While Iran has publicly stated that the Strait remains open to all except U.S.- and Israel-linked vessels, activity in practice is being actively managed and filtered.

In place of open navigation, a controlled, permission-based corridor north of Larak Island is now fully established. Vessels are routing through Iranian territorial waters, often under partial or no AIS transmission, with movement staged and sequenced rather than continuous.

Access is selective. Bulk carriers carrying agricultural cargo into Iran, LPG shipments, and tankers linked to Iranian energy exports continue to receive passage, indicating prioritization based on cargo type, ownership profile, and geopolitical alignment.

Throughout the week, this system began to scale modestly, increasing from five to seven daily transits to as many as a dozen vessels per day under managed throughput. At the same time, vessels were observed queuing north of Larak Island awaiting clearance, reinforcing that transit is being actively controlled rather than restored.

The most recent shift is the emergence of denial. Multiple vessels, including bulk carriers and livestock carriers, were turned back or left awaiting approval. Two Chinese-owned ultra-large containerships were refused passage entirely, despite assumptions of eligibility. 

More than 50 containerships now remain stranded west of the Strait, with no non-Iran-linked container vessels successfully transiting.

This confirms that Hormuz is no longer operating as a constrained corridor alone. It is functioning as a filtering mechanism, where access is determined by cargo, ownership, and geopolitical alignment, with bulk and energy flows prioritized and containerized trade disproportionately disrupted.

The Gulf Remains Full, But Movement Is Constrained

Vessel presence across the Arabian Gulf remained consistently high throughout the week, with daily counts fluctuating between roughly 600 and nearly 700 AIS-transmitting cargo vessels and tankers, despite sustained disruption to transit through Hormuz.

The composition of the fleet remained stable. Bulk carriers consistently represented the largest segment, followed by crude and product tankers, with LNG and LPG carriers and container vessels present at lower but steady levels. This distribution reflects continued demand across both energy and dry bulk flows, even as movement is restricted.

What has changed is not presence, but behavior.

Vessels are remaining in the Gulf, but are no longer moving through it at the normal pace. Operational patterns across the week point to staging, waiting, and repositioning rather than active transit. Ships are holding at anchor, adjusting routes, or positioning for potential clearance through Hormuz, rather than executing standard port-to-port voyages.

At the same time, the flag and ownership mix confirms that this is not a localized system. Panama, Marshall Islands, Liberia, China, Singapore, and Greece consistently appear among the leading registries and company locations, reinforcing that global operators remain active in the Gulf despite elevated risk.

This constraint is also visible in energy flows. LPG exports from the Gulf dropped to their lowest levels in at least 12 months, with approximately 1.5 million barrels loaded over the last week. While some cargoes continue to move under selective access frameworks, including via Iranian-controlled routes, overall volumes remain suppressed, reflecting both restricted transit through Hormuz and broader disruption across Gulf energy logistics.

This pressure extends beyond LPG. LNG presence in the Gulf is down approximately 17% compared to the weekly average, while container vessel activity is also below normal levels, reflecting continued suppression across both energy distribution and liner trade. Together, these patterns reinforce that constrained transit is not isolated to a single segment but is affecting multiple cargo types simultaneously.

Taken together, vessel presence remains high, but movement across the Gulf is increasingly constrained. 

Vessel Activity Trends in the Gulf

Operational indicators across the Gulf show a system adjusting in real time to constrained conditions.

Port calls remained relatively stable throughout the week, fluctuating between 247 and 267 daily events, indicating that vessels continue to engage with ports despite broader disruption.

At the same time, dark activity declined from 427 to 318 events over a five-day period. This reduction does not indicate normalization, but rather a shift toward more structured and potentially coordinated movement, where visibility is managed rather than entirely suppressed.

Anchoring behavior showed the most volatility. Prolonged anchoring dropped sharply from 268 vessels on March 20 to just 95 by March 24, before partial rebounds during the week. This suggests a transition from idle waiting toward more active staging, repositioning, and preparation for controlled transit.

Identity and location tampering remained consistent at 12 to 13 daily cases, reinforcing that deceptive shipping practices continue to operate steadily in parallel with legitimate commercial activity.

These trends indicate a shift toward more structured movement, where positioning, visibility, and timing are increasingly managed rather than continuous. 

Iranian Oil Exports Hold Steady Under Constraint

Iranian crude exports remained one of the most stable components of the maritime system over the past week, even as broader Gulf flows declined.

On-water volumes held steady in the range of approximately 160 to 163 million barrels, with the vast majority of cargo directed toward Asia. China continues to dominate as the primary destination, receiving roughly 80% to over 90% of Iranian exports, reinforcing its central role in sustaining these flows.

Export activity also remained active. Loading operations continued at Kharg Island, with multiple VLCCs observed loading across the week, alongside additional activity at Assaluyeh supported by SAR-confirmed vessel presence at terminals. Sanctioned vessels continued to participate in these flows, including tankers loading condensate cargoes before proceeding dark toward Asian destinations.

This dependence is extending beyond crude into gas markets. On March 25, four LPG tankers carrying approximately 2.1 million barrels of butane and propane were observed moving from Iran to Chinese destinations, including shipments carried on Chinese-owned vessels. Two of these vessels successfully transited the Strait of Hormuz, suggesting that LPG shipments aligned with Iranian exports are being prioritized within the controlled transit system. 

By contrast, only one UAE-origin LPG tanker, carrying around 270 thousand barrels, was in transit to China. This reflects a broader structural shift. U.S. tariffs disrupted a major supply channel, while Iranian strikes on UAE production facilities reduced output, leaving Iran as the most reliable remaining supplier.

At the same time, the mechanism supporting these exports is shifting.

Floating storage remains elevated at approximately 182.8 million barrels, but underlying dynamics show a drawdown. Since the beginning of the year, floating storage has declined by around 40 million barrels, while in-transit volumes have increased by roughly 50 million barrels. This indicates that exports are being sustained by releasing stored supply rather than increasing upstream production.

Operational behavior reinforces this pattern. Ship-to-ship transfers remain active in external hubs such as Malaysia and Singapore, while a significant portion of the fleet linked to Iranian crude continues to operate under reduced visibility, with roughly 129 tankers observed sailing dark.

Sanctions frameworks are also shaping flow continuity. OFAC General License U, a temporary waiver allowing the sale of already-loaded crude, has enabled sanctioned cargoes to complete voyages, supporting export stability despite broader enforcement pressure.

Taken together, Iranian oil exports are not constrained in the same way as other Gulf producers. They remain active and adaptive, but increasingly dependent on finite storage, controlled routing, and reduced-visibility operations, introducing a growing vulnerability to future supply continuity.

Russian Oil Flows Remain Elevated

Russian oil flows remained high throughout the week, with total volumes on the water exceeding 250 million barrels across crude, clean, and dirty products. Crude and condensate alone account for over 150 million barrels, continuing to move at scale despite mounting geopolitical and operational pressure.

Flows remain globally distributed. India and China dominate as primary destinations, together accounting for more than half of total volumes, followed by Singapore and Turkey. Daily arrivals continue across multiple markets, reinforcing that Russian exports are still reaching end buyers despite increasing complexity.

This continuity is being supported in part by regulatory flexibility. OFAC General License 134 continues to allow the delivery of previously loaded Russian crude, enabling cargo already in transit to complete voyages and maintaining short-term supply stability.

At the same time, the infrastructure supporting these flows is under increasing strain.

Ukrainian strikes on key Baltic export terminals at Primorsk and Ust-Luga disrupted operations during the week. Primorsk remains offline with confirmed damage to multiple storage tanks, while Ust-Luga has resumed limited activity. Prior to the disruption, approximately 43 million barrels had already been loaded from these ports in March, with an additional 67 million barrels currently on the water originating from the same facilities.

Operational signals reflect this pressure. Tankers remain stationed at affected terminals, with additional vessels en route, while AIS suppression has been observed in port areas, likely as a countermeasure to reduce targeting exposure. The fleet composition continues to include a mix of Russian-flagged, falsely flagged, and third-country registered vessels, reinforcing the continued reliance on opaque shipping structures.

These dynamics point to a growing divergence.

Russian oil flows remain elevated and operational in the short term, but export infrastructure is becoming increasingly vulnerable. While volumes in transit can buffer immediate supply disruption, sustained damage to key loading terminals introduces rising uncertainty around forward export capacity.

Yanbu Emerges as a Key Alternative Export Corridor

Saudi Arabia is accelerating crude exports through the Red Sea, reinforcing Yanbu’s role as a primary alternative to Gulf-based routing.

More than 30 tankers were observed at Yanbu port and anchorage during the week, with more than 60 crude tankers signaling the port as their destination, marking a clear increase in inbound traffic. Between March 15 and 21, approximately 22.9 million barrels were loaded, representing a roughly 20% week-over-week increase.

Loading activity remains active across key terminals, including King Fahd Industrial Port and Ra’s Al Maajjiz, with multiple VLCCs and large tankers observed during the period.

This shift reflects sustained use of Saudi Arabia’s East-West pipeline system to bypass the Strait of Hormuz. As a result, the Red Sea is becoming an increasingly critical export corridor, allowing crude flows to continue while reducing exposure to disruption in the Gulf.

Signal Risk Increases Along Red Sea Routes

As traffic shifts toward the Red Sea, the risk profile is also changing. A new U.S. MARAD advisory highlights that AIS and other onboard emissions are now being actively used for vessel targeting in the Red Sea and Gulf of Aden.

Operators are being advised to reduce signal exposure, vary routing and speed, and avoid predictable patterns. This reframes AIS from a visibility and compliance tool into a potential targeting signal in contested environments.

As a result, reduced-visibility behavior is likely to increase across Red Sea routes, reinforcing a broader move toward semi-dark operations in contested maritime corridors.

Oman Becomes the System’s Primary Workaround

Oman has emerged as the central pivot for rerouted Gulf trade. With Hormuz constrained and Bab el-Mandeb exposed, Salalah, Sohar, and Duqm are the only major ports positioned outside both chokepoint risk zones, allowing cargo to be discharged without requiring mainline vessels to enter high-threat areas.

Despite the March 11 drone strike, Salalah has become the clearest signal of this shift. Destination changes toward the port increased sharply throughout March, rising from 55 observations in early March to 71 by the week of March 19. This rerouting is not temporary. It is being reinforced by pricing, with Shanghai-to-Gulf rates rising 72% in a single week and China-to-Salalah rates increasing independently by 28%, confirming demand driven by diversion rather than local consumption.

What began as a workaround is now a system. Mainline vessels are discharging cargo in Oman and other alternative hubs, with onward movement handled by feeder vessels or overland transport into the Gulf. This model was formalized through Dubai Customs Notice 04/2026, establishing a land bridge between Oman and the UAE, while Qatar has designated Omani ports as primary substitutes for Hamad.

At the same time, Oman is absorbing additional system pressure. The collapse of Fujairah has shifted bunkering demand toward Omani ports, with ship-to-ship bunkering operations reaching record levels. 

Container activity has also surged, with anchored container vessels reaching approximately 62% above expected baselines, reflecting congestion, rapid discharge cycles, and accelerated inland movement.

Oman is also beginning to absorb shifts in energy trade flows. While total export volumes have remained relatively stable at around 1.5 million barrels per day over the past year, destination patterns are changing. March data shows increased flows toward Pakistan, the UAE, Taiwan, and China, with roughly 20% of volumes redirected away from traditional markets such as South Korea, South Africa, and Singapore. This indicates that Oman is not only facilitating rerouted logistics but also adapting to changes in global energy distribution.

Iranian strikes on Duqm and Salalah, alongside the reclassification of Omani waters as war-risk zones, indicate that the system’s primary workaround is now itself becoming a target.

This operational importance is now being matched by rising geopolitical exposure. An Indian warship deployed to Omani waters represents the only visible international patrol presence, alongside Omani and UAE maritime units operating near the coastline. At the same time, Oman has formalized a strategic partnership with the European Union, while renewed Houthi signaling points to potential escalation in the Red Sea. As the primary east-west logistics pivot, any disruption at Bab el-Mandeb would further concentrate pressure on Omani ports, freight systems, and regional energy flows.

Port Operations Absorb Rerouting Pressure

Port activity reflects the operational consequences of sustained rerouting, with disruption shifting from chokepoints into port systems.

Inside the Gulf, Jebel Ali stands out as the most consistently disrupted hub, with recurring spikes in destination changes, delays, and rollovers observed across multiple days, including peak periods with more than 80 destination changes and over 40 delay cases. Other Gulf ports, including Khalifa Port and Ad Dammam, show more intermittent disruption, with spikes in destination changes and delays appearing on specific days rather than as a continuous pattern.

Outside the Gulf, the signal is more pronounced. Ports such as Salalah, Sohar, and Khor Fakkan are absorbing displaced flows, with Salalah recording triple-digit rollovers and delays on peak days, and Sohar seeing destination changes surge to multiples above baseline levels. Khor Fakkan and Fujairah also showed sustained increases in destination changes, reinforcing the scale of rerouting pressure.

At the same time, localized stabilization appeared intermittently, with ports such as Karachi showing reduced delays and rollovers on certain days. However, these improvements remain isolated and do not reflect broader system recovery.

The pattern across the week is consistent. Routing decisions are being made dynamically rather than according to fixed schedules, with ports acting as shock absorbers for displaced cargo flows. Disruption is no longer concentrated at chokepoints alone. It is distributed across the network, where congestion, delays, and destination changes are now embedded in day-to-day operations.

Jet Fuel Supply Shock Extends Beyond the Region

Strikes on Kuwait’s Mina Al-Ahmadi and Mina Abdulla refineries on March 19 have introduced a new layer of disruption to global energy markets. Kuwait accounts for approximately 10% of global seaborne jet fuel exports, shipping just under 260,000 barrels per day out of an estimated 1.77 million bpd global seaborne trade.

Windward data shows 73 LR1 and LR2 tankers currently laden with jet fuel, including 10 signaling destinations to Europe. Eight cargoes remain trapped west of Hormuz, and no new loadings have been observed for more than three days, indicating an immediate break in supply continuity.

The impact is expected to concentrate in northwest Europe, with France, the U.S., the Netherlands, and Belgium among the primary destinations. Europe remains structurally dependent on seaborne imports, increasing its exposure to disruption.

Pricing pressure is already visible. Jet fuel was trading at just over $202 per barrel on March 17, before the latest strikes, and further tightening is expected as airlines begin contingency planning.

With global jet fuel demand at approximately 7.9 million barrels per day, the aviation sector is particularly exposed. The absence of clarity from the Kuwait National Petroleum Company on damage and recovery timelines adds further uncertainty to an already constrained supply outlook.

East Africa Fertilizer Disruption

A dual supply disruption is emerging for East Sub-Saharan Africa, signaling a broader impact beyond energy markets.

Out of 224 bulk carriers currently trapped in the Gulf, 22 typically serve the Gulf-to-East Africa fertilizer route. Since March 1, 19 of those vessels, or 86%, have stopped sailing to East Africa, implying a lane-specific shortfall of approximately 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, increasing the risk of downstream shortages across agricultural markets.

Cuba Flows Reflect Strained and Opaque Supply Chains

Flows toward Cuba remain limited, highlighting the fragility of sanctioned energy supply routes. As of March 22, only one tanker is signaling a destination toward Cuba.

The vessel, a sanctioned Russian tanker carrying approximately 749,000 barrels of crude, is broadcasting “ATLANTIC FOR ORDERS” in its AIS destination field, reflecting continued use of ambiguous signaling to obscure final delivery points.

This pattern points to both reduced visible flows and sustained reliance on opaque routing practices within sanctioned trade networks, reinforcing the vulnerability of Cuba’s energy supply under current conditions.

European Enforcement Moves to Physical Interdiction

European maritime enforcement is intensifying, shifting from administrative sanctions to direct physical action. The boarding of the sanctioned tanker DEYNA by French naval forces in the Western Mediterranean, supported by UK surveillance, marks a clear escalation toward interdiction at sea.

The vessel reflects a broader pattern of evasion, including repeated identity changes, false flag adoption, and extended AIS suppression during cargo loading. This is not an isolated case. It is the sixth confirmed boarding of a shadow fleet tanker by European forces in the past three months, alongside similar operations targeting vessels with the same behavioral profile.

At the same time, the scale of activity remains significant. Russia’s shadow fleet is estimated at 1,100–1,200 vessels globally, with roughly half designated under EU sanctions, while export volumes continue to move at scale.

The result is a tightening cycle. Enforcement is becoming more aggressive and operational, while shipping networks are adapting through reflagging, reduced visibility, and continued use of deceptive practices.

Chinese Undersea Mapping Expands Beyond Civilian Research

Chinese maritime survey activity continues to show patterns consistent with dual-use undersea mapping. The research vessel DONG FANG HONG 3 has conducted sustained operations across key regions, including the South China Sea, Philippine Sea, and Indian Ocean between March 2024 and March 2026, with 155.9 hours of dark activity concentrated near Hainan Island military facilities and deep-ocean zones critical to submarine warfare.

This is not an isolated case. Four additional Chinese research vessels display similar deployment patterns, indicating a coordinated, state-directed effort.

The operational focus suggests clear military relevance, supporting submarine navigation, detection, and concealment, alongside broader oceanographic intelligence. These activities point to a systematic mapping program operating under the cover of civilian research.

Black Sea Risk Expands Beyond the Gulf Theater

A new strike highlights expanding risk beyond the Gulf. The sanctioned tanker ALTURA, a Sierra Leone-flagged Suezmax carrying approximately 1 million barrels of crude, and designated by both the EU and UK, was struck near the Bosphorus by a suspected naval drone. The attack targeted the engine room. No injuries were reported, but the vessel was broadcasting “Not Under Command” as of 00:30 UTC on March 26.

This incident reinforces the spread of kinetic risk into Russian-linked export routes outside the Gulf, indicating that maritime threat exposure is no longer confined to a single region but expanding across multiple operational theaters.

Security Risk Expands Across Maritime Theaters 

The security environment remains elevated, with at least 20 vessels targeted or attacked and 10 energy and port infrastructure sites impacted since the start of the conflict, underscoring sustained pressure on both maritime operations and critical logistics nodes.

Military presence across the Gulf is significant, with over 100 naval and law enforcement vessels deployed, including firefighting and response units clustered around incident zones, indicating ongoing activity and potential unreported events.

Despite this escalation, international response remains limited. Key actors, including the EU, NATO, Japan, and South Korea, have yet to establish a coordinated escort framework, leaving commercial shipping exposed to continued threat activity.

At the same time, risk is expanding beyond a single region. Indian naval forces escorted Indian-flagged LPG tankers in the Gulf of Oman following their transit through Hormuz, highlighting a shift toward selective, voyage-specific protection rather than broad-based security coverage. In parallel, Houthi signaling points to a potential reopening of the Red Sea front, increasing the risk of renewed disruption at Bab el-Mandeb. Oman’s growing role as a logistics hub, combined with its recent alignment with the EU, further increases its exposure as tensions rise.

Taken together, maritime risk is not localized. It is multi-theater, interconnected, and increasingly aligned with both military signaling and commercial routing patterns.

Outlook

The current trajectory points toward continued fragmentation rather than stabilization.

Hormuz is unlikely to return to open transit conditions in the near term. The controlled corridor model is now established, with access increasingly shaped by geopolitical alignment, cargo type, and ownership structures. As denial patterns expand, containerized trade and non-aligned operators will remain disproportionately affected.

At the same time, alternative systems will continue to scale. Oman’s role as a logistics and energy hub will deepen, while Red Sea routing and Yanbu exports will remain critical to offset Gulf constraints. However, these workarounds introduce new vulnerabilities, particularly as security risks expand across adjacent regions.

Energy markets will remain uneven. Iranian exports are stable but reliant on finite storage and reduced-visibility operations. Russian flows continue, but infrastructure strain introduces forward risk. Disruptions to jet fuel, LPG, and fertilizer flows indicate that second-order impacts are already spreading beyond crude markets.

Security dynamics will further complicate operations. The absence of coordinated international protection frameworks, combined with expanding threat activity across the Gulf, Red Sea, and Black Sea, suggests that risk exposure will remain high and geographically distributed.

The system is holding, but under pressure.

What comes next will depend less on whether flows continue and more on how long the current workaround model can sustain them.