U.S. Submarine Sinks Iranian Frigate in Historic First Since WWII

The March 4 incident marked the first time an American submarine had torpedoed an enemy vessel since the last days of World War II.

Mar. 14, 2026 at 8:00pm

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The U.S. Navy has sunk an Iranian frigate, the Dena, in the Indian Ocean, marking the first time an American submarine has torpedoed an enemy ship since the end of World War II. The incident, which occurred on March 4, resulted in the deaths of at least 87 of the Dena's 180-man crew, with 32 rescued by the Sri Lankan navy and the rest still missing.

Why it matters

The sinking of the Iranian frigate is a significant milestone for the U.S. submarine community, as it demonstrates the capabilities of American submarines in combat conditions. The incident has also sparked debate about the political ramifications of such actions and the potential for increased submarine warfare exercises in the future.

The details

According to the Department of Defense, a Los Angeles-class submarine encountered the Dena off the coast of Sri Lanka as it was returning home from naval exercises hosted by India. In international waters, the sub fired two torpedoes, one of which sank the vessel. Footage and periscope views released by the DOD appear to show the Dena lifted out of the water by the blast before sinking almost vertically.

  • The incident occurred on March 4, 2026.
  • The last time a U.S. submarine sank an enemy ship was on August 14, 1945, the day Japan's surrender ended World War II.

The players

USS Charlotte (SSN-766)

A Los Angeles-class submarine built by Newport News Shipbuilding in Virginia and commissioned in 1994. It is believed to have been the submarine involved in the sinking of the Iranian frigate.

Dena

An Iranian frigate that was sunk by the U.S. submarine in the incident.

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What they’re saying

“It's an exciting event for submarine personnel to know that we finally were tested in combat, in actual combat conditions, and that everything works the way that it's supposed to.”

— David Johnston, Former submariner and submarine historian

“It is pretty much a consensus from SubVet members here in Groton that the US Navy submarine was performing their duties as ordered.”

— Steve Ricard, Commander of the Groton chapter of United States Submarine Veterans

What’s next

The judge in the case will decide on Tuesday whether or not to allow Walker Reed Quinn out on bail.

The takeaway

This incident highlights the capabilities of U.S. submarine forces and the potential for increased submarine warfare in the future, as it serves as a message to adversaries like Russia and China who are investing in their own submarine fleets. However, it also raises questions about the political ramifications of such actions and the need to balance military objectives with the goal of deterring war.