Traffic through the Strait of Hormuz has collapsed to roughly 5% of its pre-war level, cutting monthly transits from about 3,000 ships to just 154 in March. Major container lines have changed service patterns, omitting Gulf calls, shifting to nearby ports, or sending vessels on much longer loops, according to maritime movement data and industry trackers. The disruption has squeezed fuel and product flows and strained liner schedules across Asia, Europe and the Middle East. That change is forcing shipping companies and shippers to absorb longer voyages and higher costs while regional chokepoints such as the Malacca Strait gain fresh strategic attention.

How traffic through Hormuz collapsed

Before late February, roughly 3,000 vessels crossed the Strait of Hormuz each month. That figure included tankers carrying about 15 million barrels per day of crude and other oil products, an amount equal to roughly one-fifth of global oil trade, according to shipping analytics cited by maritime trackers.

The war in Iran has altered that pattern fast. In March, trackers recorded only 154 transits. Overall movement through the strait has run at about 5% of the pre-war average in recent weeks, industry analysts say.

Those numbers have consequences for energy and goods flows. Refined product supplies tightened, especially in Asian markets.

And more ships appear to be moving out of the gulf than into it, signaling that operators are avoiding the main international lane rather than waiting out the crisis.

"The disruption is both rapid and rare," said Dimitris Ampatzidis, maritime risk and compliance manager at Kpler.

How carriers are changing routes

Container networks need predictability. They run fixed rotations and tight port sequences. When a chokepoint closes, carriers change those routines fast.

Data from a vessel-tracking analysis of 49 container ships shows three broad responses. Some operators kept ships close by and used alternate Gulf ports.

Others rerouted inside the wider Indian Ocean. A smaller share sent vessels completely outside the region.

Mastheads

CMA CGM and COSCO largely stayed within the Arabian Peninsula, diverting to alternative local ports rather than exiting the region. CMA CGM moved 88 percent of the sample ships to Arabian Peninsula routes, while COSCO kept 100 percent close to the peninsula, the tracker found.

Hapag-Lloyd adopted a mixed approach. Roughly 17 percent of its ships served Arabian ports, 67 percent shifted into the Indian Ocean, and 17 percent were routed outside the region. Maersk showed the heaviest shift outside the region, with 31 percent of the sample vessels routed beyond the Indian Ocean loop. MSC balanced between Arabian Peninsula and Indian Ocean routings.

Those choices reflect different risk tolerances and network needs. Some lines prioritized keeping Gulf port calls. Others prioritized preserving long-haul loops and schedule reliability by skipping Gulf calls and rebalancing capacity elsewhere.

Which ports and passages absorb diverted volumes

When ships avoid Hormuz, nearby Gulf hubs become temporary gathering points. Ports such as Jebel Ali, Khalifa Port, Dammam and Hamad are central to regional liner rotations. They act as import gateways and transshipment nodes for feeder networks linking the Gulf to Asia, Europe and Africa.

But longer-distance detours shift pressure to other narrow passages. The Strait of Malacca is now a bigger focus. It already carries about 22 percent of global maritime trade and moves more oil than Hormuz in aggregate, according to regional and energy-center data. In 2025 the Malacca route handled about 23.2 million barrels per day in the first half, equal to nearly 29 percent of sea-borne oil flows, the figures show.

Some very large crude carriers avoid Malacca because of draft limits. But most commercial tankers and many container ships still transit the strait. If traffic diverted from Hormuz continues to favor routes through Southeast Asia, congestion and transit delays in Malacca and the Singapore approaches could rise.

Market and cost effects on trade lanes

Carriers are absorbing real operational costs. Slower sailings and longer distances mean higher bunker fuel use and longer vessel time at sea. They also complicate schedule integrity across feeder and long-haul services. Shippers face longer lead times and thinner visibility for cargo in transit.

Logistics managers already report cascading schedule changes. When a liner omits a Gulf call, its planned connections in Asia and Europe shift. That forces cargo to move on alternate loops or wait for replacement sailings. The net effect is more time in port or on the water and pressure on freight rates for certain lanes.

For oil and refined products, the decline in Hormuz throughput has tightened regional supplies. Analysts point to growing shortages of refined products in Asia. That pressure can lift crude and product tanker rates, while also pushing spot fuel prices higher for container ships that must take longer routes.

Those cost pressures matter to corporate buyers and end consumers. They feed into inventory costs for manufacturers and delivery costs for retailers. And they alter decisions about routing, inventory placement and hub use in liner networks.

Iranian authorities have at times restricted the established international lane and promoted alternative corridors hugging the Iranian coastline. The Revolutionary Guard published maps marking new routes through Iranian territorial waters and identified parts of the former international lane as a "danger zone."

That shift reduces the number of vessels willing to use the official IMO shipping corridor and increases the share of traffic that sails close to Iranian ports. Regional and international operators now face an added layer of navigational complexity and potential inspections.

At the same time, many vessels in the gulf are regional ships that continue routine local voyages. More than 800 vessels remain in the gulf region, but analysts say "stranded" isn't the right label for all of them. Local fleets and certain operators continue to move cargo on regional routes.

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As Dimitris Ampatzidis of Kpler put it, "The disruption is both rapid and rare," underscoring the sudden rerouting, longer voyages and higher costs shipping lines now face.

This article was created with AI assistance.