The U.S. Navy’s blockade along Iran’s southern coastline is proving highly effective. Maritime Executive reported on September 28, 2026, that this blockade has nearly eliminated the flow of goods through key ports like Bandar Abbas, which previously managed about 80% of Iran’s trade. In response, Tehran has turned its focus northward. The volume of cargo in the Caspian Sea saw a remarkable 50% increase between March and August 2026, as reported by the governor of Gilan province.
Iran’s Arms Shipments to Russia
Following the difficulties faced by Russia in its war against Ukraine, Iran expedited the transfer of military supplies to Russia. Reports indicate that Iran delivered over 300,000 artillery shells and a million rounds of ammunition across the Caspian Sea. This burgeoning maritime route is no secret; just a week before, Israeli forces attacked Iran’s naval base at Bandar Anzali to disrupt these arms shipments. U.S. officials confirmed that Russia has been sending drone components to Iran using the same pathway, which is crucial for bypassing Western sanctions.
On September 10, 2026, Ukrainian drones targeted the port of Makhachkala, emphasizing its strategic importance along the Russia-Iran logistics corridor across the Caspian Sea. This corridor has allowed both nations to circumvent economic restrictions imposed by the U.S. and its allies. Yet the efficacy of U.S. sanctions appears to be lagging when it comes to this emerging maritime trade route.
The Expansion of Iran’s Naval Capabilities
Despite facing sanctions since 2018, Iran’s maritime capabilities are on the rise. The head of Khazar Sea Shipping Lines, Iran’s Caspian shipping arm, announced in November 2024 that the company had acquired new dry cargo ships and was planning further expansions. By the end of 2026, Islamic Republic of Iran Shipping Lines anticipates boosting its capacity to an impressive 150,000 tons.
While the 2018 Aktau convention restricts non-coastal states from deploying military forces in the Caspian Sea, Iran has yet to ratify it fully. Consequently, Ukraine remains the sole nation actively disrupting illicit activities on these waters, including a significant attack on Iranian cargo vessels in July 2026. Although criticized by Tehran as a criminal act, these interventions reveal the potential for maritime opposition against Iran’s arms operations.
Proposed Solutions for Effective Sanctions
To fortify sanctions and curtail illegal arms shipments, the U.S. must broaden its scope beyond oil tankers to include the vessels transporting arms and their associated operators and ports. The U.S. Treasury should conduct thorough reviews to align sanction lists with other Western allies like Canada and the EU, minimizing the risk of sanctions evasion.
Given that the Caspian Sea is landlocked, the U.S. government can strategically monitor important ports such as Amirabad and Astrakhan. This surveillance should be coordinated with allies like Israel and Ukraine to ensure a united front against violations. Additionally, evaluating whether shipyards providing hulls to sanctioned Iranian carriers fall under existing sanctioning laws is imperative. If feasible, sanctioning these yards would significantly impact Iran’s shipping capabilities.
Lastly, the release of information by intelligence agencies following strikes on contested cargo ships could undermine Iranian propaganda. The U.S. Treasury should also extend its actions targeting Russian channels that facilitate trade in Caspian freight, ensuring comprehensive measures are in place to identify and curb illicit transactions involving Iranian shipping operations.