Iran's Caspian Pivot: Can an Undersea Trade Route Cushion a Blockaded South?

TEHRAN, Iran — With American warships barring access to Iran's southern harbours, Tehran is scrambling for alternative ways to move crude oil out of the country and essential food and merchandise in. Among the options being explored, the Caspian Sea along Iran's northern coastline stands out as a potential window to the outside world — though one increasingly squeezed by environmental and logistical strain.

The urgency follows a diplomatic dead end. United Nations efforts to halt the conflict between Tehran and Washington have collapsed after US President Donald Trump dismissed an Iranian offer to reopen the Strait of Hormuz as unacceptable. With no resolution in sight in the war launched by the United States and Israel on February 28, Iran is being forced to redraw the map of its own trade.

The Caspian is the world's largest enclosed inland body of water, and its shores are shared by Iran, Russia, Azerbaijan, Kazakhstan and Turkmenistan. For most of the Islamic Republic's modern history, the overwhelming share of its seaborne commerce has moved through its southern ports on the Persian Gulf and the Gulf of Oman. Now, with a US naval embargo in place and airstrikes having damaged port infrastructure, officials are looking north — and to overland frontiers.

Physical limits complicate the pivot. Shipping on the Caspian has been squeezed in recent years by receding water, and the trend is accelerating. In April, UN Environment Programme Executive Director Inger Andersen said levels had fallen by roughly 2 metres (6.6 feet) since the 1990s, with projections warning of a further drop of between 8 and 21 metres by the end of the century. That is a shallow-water problem with direct commercial consequences for a fleet designed for larger seas.

Iranian officials acknowledge the erosion. Shahram Fadakar, director general of the Department of Environment's Office for Coastal and Marine Ecosystem Protection, told local media that levels have been declining by more than 20cm a year over the past two to three years — a rate he warns could affect trade among all five littoral states, Iran included. Dredging, port reconstruction and rising insurance costs are the predictable downstream effects.

The practical hit is already measurable. Masoud Polmeh, secretary-general of the Shipping Association of Iran, said this month that northern ports once accommodated berthed vessels of up to 6,000 tonnes, but can now take only 4,000-tonne ships. He also described Iranian vessels transiting the Caspian by way of Russia's Volga River grounding on falling water, sometimes sitting motionless for days or weeks until crews were extracted. At least, Polmeh said, that has not yet occurred in Iranian ports.

The redirection of freight is also choking the country's land frontiers. While the north has so far escaped direct military attack, Vali Kaleji, an independent researcher on Russia, Central Asia and the Caucasus, said the shift in logistics has placed enormous strain on Iran's borders with neighbours. At the Norduz crossing with Armenia, as many as 1,800 trucks have been queued for days at a stretch to enter Iran; at other terminals, waits run 10 to 15 days.

Kaleji cautioned that border snarls are not solely the product of cargo rerouting. Limited terminal capacity, cumbersome customs procedures, weak road infrastructure and active construction projects have all added to the delays. He added that sanctions on Iranian airlines have pushed large numbers of travellers towards crossings with Armenia and Turkey, further crowding the same facilities that freight depends on.

East of the Caspian, the picture is more promising. A rail link gives Iran access to Turkmenistan, Kazakhstan and China, an axis that could carry a significant share of northern-bound trade. To the west, however, Iran's rail freight links with the South Caucasus — severed during the First Nagorno-Karabakh War of 1988 to 1994 — remain out of service. Reviving the Soviet-era Julfa–Nakhchivan line, Kaleji said, depends on Armenian-Azerbaijani peace progress and on implementing the US-backed TRIPP transit corridor. Because a large share of traffic on the western arm of the North-South Transport Corridor runs over that missing link, its absence is described as a principal brake on expanding trade precisely when southern maritime routes are blocked.

Official figures suggest meaningful change. Ports and Maritime Organisation chief Mohammad Shakibi-Nasab said last month that Iran has 300 million tonnes of nominal port capacity, of which just 30 million tonnes is tied to the northern ports. Even so, the northern terminals' share of essential goods transport has climbed from 18 percent before the war to about 30 percent today. Scale remains a stubborn handicap: a single vessel using a southern port can haul the equivalent of 20 Caspian-going ships.

Officials have not disclosed which commodities, or in what volumes, have actually moved north — including through the Caspian ports of Anzali, Amirabad and Nowshahr. But there are indications, particularly on the import side. In early September, Gilan governor Hadi Haghshenas said container arrivals at Caspian ports rose 50 percent year on year during the five Iranian calendar months ending August 22. He also noted that northern ports sit closer to Tehran, Isfahan and Arak than the southern Port of Shahid Rajaei, potentially cutting the overland haulage cost of delivering imported goods to end users.

Looking further ahead, Haghshenas said the China–Aktau–northern Iran corridor — rail from China across Kazakhstan to Aktau, then by ship to Caspian ports and onward by road — could broaden regional commerce. Alongside that, the Iranian government is working to complete the missing sections of the Rasht–Astara railway, the spine of any genuine north-south corridor.

Taken together, the northward shift is less a replacement for Hormuz than an emergency substitute. It is happening under blockade, on a water body that is itself shallowing, with the country's most important western rail link missing and land crossings already saturated. Iran's planners are clearly treating the Caspian as a strategic hedge — but the numbers suggest it can cushion a blockade rather than end one.