ARA San Juan (S-42)

ARA San Juan (S-42) was a TR-1700-class diesel-electric submarine in service with the Submarine Force of the Argentine Navy from 1985 to 2017. It was built in West Germany, entering service on 19 November 1985, and underwent a mid-life update from 2008 to 2013.

On 15 November 2017, San Juan went missing with 44 crewmen during a routine patrol in the South Atlantic off Patagonia. She was believed to have suffered an electrical malfunction, and a multi-nation search operation was mounted. Within hours of San Juan's last transmission, an acoustic anomaly consistent with an implosion was detected in the vicinity of the vessel's last known location. When the submarine was not located for a week, the crew were presumed dead by the Argentine government. On 30 November, the search and rescue operation was abandoned.

The Argentine Navy reported on 16 November 2018 that the wreck of San Juan had been found at a depth of 907 metres (2,976 ft), 460 kilometres (290 mi) southeast of Comodoro Rivadavia. The submarine's imploded wreckage was strewn over an area of 8,000 square metres (86,000 sq ft).