Why Greater Tunb Matters Near the Strait of Hormuz

US strikes on Greater Tunb on Wednesday thrust one of the most sensitive points at the entrance to the Strait of Hormuz back into the center of the confrontation, after US Central Command said it hit coastal defense systems, storage sites and cruise missile launchers in a 90-minute assault. CENTCOM said the strikes were aimed at reducing Iran’s ability to attack commercial vessels in the strait. Greater Tunb, one of three Emirati islands occupied by Iran since 1971, hosts a military airfield, Iranian Revolutionary Guard Corps Navy bases, garrisons and missile assets used to monitor nearby shipping lanes. Former IRGC Navy commander Alireza Tangsiri had called the island vital to Iran’s control of the strait because it sits between the main inbound and outbound shipping routes. Tangsiri, who was killed in an airstrike in Bandar Abbas on March 26, said in an earlier state television interview that losing Greater Tunb would mean losing control of transit routes through the Strait of Hormuz. Its location, he said, gave Iranian forces the ability to monitor maritime traffic and shape its movement. Tangsiri also tied Abu Musa and Sirri islands to Iran’s gas fields and Gulf trade, warning that the loss of Abu Musa could lead to the loss of Sirri and its military positions, gas fields and trade routes. He had overseen the expansion of IRGC bases across the islands, including the military airfield on Greater Tunb and facilities on Sirri. Islands and shipping lanes Greater Tunb is part of a chain that includes Abu Musa, Lesser Tunb, Qeshm, Larak, Hormuz and Sirri. Studies have described the islands as forming Iran’s “defensive arc” around the strait. Iranian officials have likened them to “unsinkable aircraft carriers” because they host anti-ship missiles, surveillance posts and naval bases. Greater Tunb’s importance also lies in its proximity to the two main shipping lanes. Tehran says vessels must follow routes and schedules set by Iranian authorities and secure prior approval. Washington is pressing for a southern route along the Omani coast that would fall outside Iranian control. The routes have become a central point of dispute since the Islamabad memorandum of understanding on June 17. Iran interprets its fifth provision as granting Tehran a role in regulating passage. The United States says the Strait of Hormuz is an international waterway that cannot be subjected to unilateral permits or fees. Greater Tunb is a forward military outpost in Iran’s network of control over the strait. The strikes were aimed at disabling coastal defense and missile sites that could be used against vessels and weakening Iran’s ability to impose its rules on shipping.