| Date | March 4, 2026 |
| Country | 🇮🇷 Iran |
| Force | Navy |
| Conflict | 2026 Iran Conflict |
| Location | South of Galle, Sri Lanka |
| Ship Class | Moudge |
| Ship Name | IRIS Dena |
| Hull Number | 75 |
| Event type | Sunk -1 |
Third Moudge-class frigate, torpedoed by a U.S. Navy submarine on March 4, 2026, approximately 20 nautical miles south of Galle, Sri Lanka. Department of War released periscope footage showing a Mk 48 torpedo striking beneath the stern. Sri Lanka's Deputy Foreign Minister confirmed 80 sailors killed, with 32 rescued from a crew of 180. The vessel was returning from the Indian Navy's MILAN exercise in the Bay of Bengal. The sinking marked the first U.S. torpedo attack on an enemy warship since World War II.
GlobalMilitary.net fleet records attribute 30 Islamic Republic of Iran Navy hulls to the war that began on February 28, 2026. Every frigate and every corvette on the fleet list is marked sunk, leaving the regular navy without a single blue-water surface combatant.