The sinking of IRIS Dena marked a rare moment in modern naval warfare history

Cultures · Published 10 October 2026 Swipe more like this →

In short: In March 2026, the Iranian frigate IRIS Dena was sunk by a United States submarine off the coast of Sri Lanka. This event was historically significant, as it represented the first time a submarine had successfully engaged and destroyed a surface ship in active combat since the Falklands War in 1982.

Commissioned in 2021, the IRIS Dena was a Moudge-class frigate named after Mount Dena. Measuring 94 meters in length and displacing between 1,300 and 1,500 tons, the vessel was a notable technological milestone for the Islamic Republic of Iran Navy. It was the first Iranian ship to utilize Bonyan 4 engines, which provided a total output of 20,000 horsepower. Beyond its propulsion, the ship featured an Asr phased array radar and a bow thruster system designed to enhance maneuverability in diverse maritime environments.

The ship gained international attention during its 2022–2023 circumnavigation alongside the IRIS Makran, a mission described as historic for the Iranian fleet. By February 2026, the Dena had traveled to India to participate in the International Fleet Review in Visakhapatnam and the 2026 Milan exercise. Following these engagements, the ship was in international waters near Galle, Sri Lanka, when it transmitted a distress call on 4 March 2026. Despite rescue efforts by the Sri Lanka Navy and Air Force, the ship sank, resulting in the recovery of 87 bodies and the rescue of 32 sailors.

The United States confirmed that the USS Charlotte, a Los Angeles-class submarine, was responsible for the sinking. The submarine fired two Mark 48 torpedoes, one of which struck the Dena. At the time of the incident, the frigate was reportedly unarmed, adhering to protocols associated with the naval exercise it had recently attended. This engagement stands as the only instance of an American submarine sinking a ship since the Pacific theater of World War II, and the only combat sinking by any submarine globally since the 1982 destruction of the ARA General Belgrano.

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