Until March 2026, the primary threats to developing trade corridors across the Caspian Sea seemed to be inadequate infrastructure and falling water levels. Then Israel targeted Iranian naval assets in the sea, followed in July by a Ukrainian attack on Iranian military shipments in the waterway. Conflict in the Caspian Sea has made it clear that physical maritime security is essential to making the east-west route a viable, reliable alternative conduit for critical resources. 

The Trans-Caspian International Transport Route, the east-west route known as the Middle Corridor, provides 4,250 kilometers of rail lines and 500 kilometers of sea connections between Europe and Central Asia, transiting through Türkiye, Azerbaijan, Kazakhstan, and Uzbekistan. The Middle Corridor will also potentially connect further to China via a new rail line through Uzbekistan and Kyrgyzstan and link Armenia and Azerbaijan through the 42-kilometer Zangezur Corridor thanks to the U.S.-sponsored TRIPP deal. 

A second route, the International North-South Transport Corridor, once developed, would span 7,200 kilometers and connect Russia to the Persian Gulf, via the Caucasus, the Caspian Sea, and India. Conceived more than 20 years ago, the proposed north-south route has gained new life due to Russia’s need for alternative routes since the full-scale war in Ukraine and India’s interest in a route to the Arctic circumventing China.

Both trade routes highlight the Caspian region’s centrality for supply chain resilience and the expansion of connectivity. Nevertheless, many bottlenecks prevent these ambitions from reaching fruition. The World Bank argues that trade along the route could triple by 2030 if ten priority actions are taken immediately. These include improving port infrastructure and rail connections, increasing the quantity of rolling stock, and addressing customs, logistics, and governance challenges.

The declining water level of the Caspian Sea exacerbates these challenges. Russia has been damming the Volga River, which accounts for approximately 80 percent of the Caspian’s water. Kazakhstan’s Ministry of Natural Resources attributes the shallowing and retreat of the Caspian Sea to climate change. Although the shallowing began in the 1990s, the water level has declined to a new low in 2026. Higher air and water temperatures contribute to further evaporation. Dredging is a short-term, and expensive, solution and ferry transport – crucial for exports of critical minerals from Central Asia – already has been reduced along some routes. Although the Middle Corridor states are well aware of the problems, with Kazakhstan declaring the dropping water level a state of emergency in 2023, the fossil fuel and maritime industries they depend on further contribute to the Caspian Sea’s shallowing.

The Caspian region also faces geopolitical headwinds. Russia and Iran have historically blocked Caspian pipeline projects that dilute their own leverage on fossil fuel exports. China would seem to benefit from an alternative trade route given the interruptions to other routes that Russia’s war in Ukraine has caused. Some observers see China treading cautiously with the China-Kyrgyzstan-Uzbekistan railway to avoid a negative reaction from Russia.

Others see China’s potential for greater involvement as counterproductive to a trade route for critical minerals that is supposed to provide an alternative to Chinese supply chains. U.S. opposition to a sanctioned Chinese company serving as operator for a new deepwater port of Anaklia on Georgia’s western Black Sea coast, a project seen as important for the further expansion of the Middle Corridor, may have contributed to the Georgian government’s decision to retain control. 

However, since 2022, but particularly in 2026, hard maritime security issues on the Caspian Sea have increasingly moved to the forefront. 

The North-South Vector: Sanctioned Trade and Arctic Gateway

The North-South vector of the Caspian Sea involves conflict-related trade flows between Russia and Iran and a framework for a multilateral trade route involving India. With the Black Sea under Ukrainian attack, Russia’s 2 million tons of annual wheat deliveries to Iran are now being shipped via the Caspian Sea. In 2026, Russia also began sending parts for Geran-2 drones to Iran to replenish its supplies used in the war with the U.S. and Israel. Ukrainian sources allege that Russian-made drones based on Iranian technology have been found in the UAE, indicating Russian transfer of their own production to Iran.

Iran has been shipping ammunition and three types of drones to Russia via the Caspian Sea for the war in Ukraine, as CNA explored in a January 2025 report on the Russia-Iran Relationship. Iran also provided related training and facilitated Russian production of Iranian drones inside Russia. The two countries used “dark port calls” – that is, sailing without using required transponders – to mask their covert Caspian Sea transits. 

Such efforts did little to camouflage the arms trade in the Caspian Sea. Russia has launched attacks on Ukraine from its Caspian flotilla. For its part, Ukraine views Iranian and Russian vessels involved in weapons trade for Russia’s war as fair targets. One Iranian sailor was killed in a July 25 Ukrainian drone attack on a cargo ship. On March 18, Israel attacked the Iranian port of Bandar Azali, its first Iranian target on the Caspian Sea, to disrupt Iran’s supplies of military equipment from Russia.

These attacks raised concerns in India, which signed an agreement with Iran in 2024 to operate the Shahid Beheshti terminal at Chabahar Port on the Gulf of Oman. New Delhi is eager to develop the North-South trade corridor with Russia, Iran, and Caspian states such as Kazakhstan and Azerbaijan. India and Russia signed an agreement in December 2025 for partnership in the Arctic, including using the North-South corridor to expand Indian access to the region. Russia has been enthusiastic about greater Indian participation to offset the prevalence of “unfriendly countries” and balance China’s greater activism in the Arctic.

The East-West Corridor: Economic Potential and Security Threats

Since 2022, the Caspian region has grown in importance as a source and transit region for Western energy and mineral resources. 

Energy remains the most important regional export. Over 90 percent of Azerbaijan’s oil and gas production is offshore in the Caspian region. Kazakhstan and Turkmenistan, meanwhile, extract most oil and gas onshore and historically have exported it via pipelines through Russia and China. However, even before Ukraine’s systematic campaign against Russian energy infrastructure in 2026, Kazakhstan had increased shipments of oil across the Caspian Sea via the Baku-Tbilisi-Ceyhan (BTC) pipeline to avoid Russian transit, although exports through the BTC pipeline still only account for 2.3 percent of Kazakhstan’s oil production. Turkmenistan, meanwhile, has three gas pipelines toward China in operation, with a long-delayed fourth in the works. Although a long-discussed Turkmenistan-Afghanistan-Pakistan-India pipeline remains stalled, U.S. and Turkish officials have spoken highly of a potential subsea Trans-Caspian Gas Pipeline. 

The Trans-Caspian Gas Pipeline, first proposed at least 25 years ago, would connect Turkmenistan to Azerbaijan, and from there continue onward toward Türkiye. Until 2018, the Caspian’s uncertain legal status gave Russia and Iran de facto vetoes over progress. However, the 2018 Convention on the Legal Status of the Caspian Sea clarifies the right of the littoral states to lay pipelines and cables through their own sea/lakebed regions, establishing Turkmenistan and Azerbaijan’s right to lay a connector pipe. Iran is finally moving toward ratifying the convention, enabling it to go into force. A realized Trans-Caspian Gas Pipeline, coupled with expanding onward pipelines from Azerbaijan, would offer Turkmenistan’s gas a narrow route to Türkiye and Western markets free of Russian or Iranian control. As noted by U.S. Secretary of State Marco Rubio during a recent Senate hearing, this would be “in the best interests of the United States and its allies.”

Central Asia’s global importance is growing beyond just energy. Both the U.S. and the EU have signed agreements, particularly with Kazakhstan, to expand access to critical minerals. For these to reduce the dependence of the U.S. and its allies on adversaries, however, they must make it out of Central Asia. The Caspian Sea is the only route out of the region that does not require transit through Russia, China, Iran, or Afghanistan. The broad Middle Corridor project to build alternative ground links through Central Asia toward Europe has produced some important infrastructure investments, and freight has grown. But more remains to be done, including with the Department of State’s Trans-Caspian Enterprise Fund, established in 2026 to catalyze private-sector investment in trade links across the South Caucasus and Central Asia. For example, bottlenecks impeding Caspian Sea transportation require further investments in port infrastructure and shipping. 

Advocates for expanding trans-Caspian transport links in Kazakhstan suggest that it is an important means of risk management, and the cost advantage of traditional Russian routes can be reduced by investment. Kazakhstan, Azerbaijan, and Turkmenistan could all benefit from expanding an independent Caspian Sea export route, but they would be wise to focus on securing the route. The value proposition for these states, global investors, and the U.S. and its allies is to diversify trade routes away from Russia, in particular. However, Russia and Iran have both repeatedly demonstrated their capacity and willingness to disrupt maritime traffic and infrastructure important to Western or global supply chains. Threats could range from anchor drags and sabotage to mine-laying, interdiction, or military attacks. Such threats would require only modest capabilities to address. 

Central Asia offers an important alternative source for critical minerals and energy for the global economy. In recent years, the U.S. and Europe have clearly recognized this. However, realizing Central Asia’s potential to diversify Western sources of critical raw materials requires secure navigation across the Caspian Sea. Azerbaijan, Turkmenistan, and Kazakhstan should each – and ideally, collectively – focus on maritime monitoring and presence as cross-Caspian trade expands. Ashgabat, Astana, and Baku have already invested in new platforms, including uncrewed systems. Targeted US and European security cooperation with these states should focus on building and sustaining capability that makes the most of new systems. This offers a clear and targeted way to enhance Caspian security and address its old and new security challenges, thus facilitating the sustainable development of the Caspian trade corridors. 

The views expressed are those of the authors and do not represent those of CNA or its sponsors.