Coordinates: 55°25′44″S 26°11′29″W / 55.42889°S 26.19139°W
The South Sandwich Trench is a deep arcuate trench in the South Atlantic Ocean lying 100 km to the east of the South Sandwich Islands. The trench is produced by the subduction of the southernmost portion of the South American Plate beneath the small South Sandwich Plate. The South Sandwich Islands constitute a volcanic island arc which results from this active subduction. Mount Belinda on Montagu Island is an active volcano.
It is the deepest trench of the Southern Atlantic Ocean, and the second deepest of the Atlantic Ocean after the Puerto Rico Trench.
The trench is 965 km long and has a maximum depth of 8,428 metres below sea level. This location, at 55°40'S, 025°55'W, is called Meteor Deep. It is 122 km northeast of Zavodovski Island.
The southernmost portion of the South Sandwich Trench reaches south of 60°S and therefore into the Southern Ocean, thereby containing the maximum depth of that Ocean at 60°00'S, 024°W, with a depth of 7,235 meters.