Larsen Harbour, Natural inlet in South Georgia and the South Sandwich Islands.

Larsen Harbour is a 4.2 km narrow inlet of volcanic rocks and sheeted dykes, the Larsen Harbour Formation, branching off Drygalski Fjord 4 km west-northwest of Nattriss Head at the southeast end of South Georgia. Hash Island sits in its entrance, Williams Cove and Scoresby Point lie on the north side, and Bonner Beach runs along the south shore. Mountains drop steeply into the sea and glaciers calve into the almost land-locked water.

The Second German Antarctic Expedition first mapped this inlet in detail during the early 1900s, recording its geography and features. This early survey work provided the foundation for all subsequent knowledge of the location.

The inlet is named after Captain Carl Anton Larsen, the Norwegian explorer credited with founding the Antarctic whaling industry and the whaling station at Grytviken. He also made the first discovery of fossils on the Antarctic continent, work recognised by the Royal Geographical Society's Back Grant. The name was given by Wilhelm Filchner's Second German Antarctic Expedition of 1911–12, which charted the harbour.

Visits are only possible during the brief Antarctic summer when ships can navigate these waters safely. Access requires substantial travel time and should be planned well in advance with experienced operators.

Several glaciers flow directly into the harbor waters, creating a dynamic landscape where ice meets sea. Hash Island marks the entrance to this deep natural formation.