Sinking of IRIS Dena

During the 2026 Iran war, the Iranian Navy frigate IRIS Dena was torpedoed and sunk by the United States Navy's Los Angeles-class submarine USS Charlotte in the Indian Ocean.

Dena had recently taken part in the International Fleet Review 2026 naval exercise hosted by India and was returning home when it was sunk in international waters, approximately 19 nautical miles (35 km; 22 mi) off the coast from Galle, Sri Lanka. On 4 March, Charlotte fired two Mark 48 torpedoes at Dena, of which one hit the frigate. Its Bell 212 helicopter appeared to have not been present during its sinking.

This was the first instance of a nuclear-powered submarine sinking an enemy surface vessel since the sinking of ARA General Belgrano by Royal Navy nuclear submarine HMS Conqueror during the Falklands War. It is the first such naval action by a US Navy submarine since the Pacific theater of World War II. It is the fourth ship that has been sunk by a torpedo since 1945 and a rare example of an attack on a foreign warship not taking part in open hostilities.