The 2016 austral spring was characterized by the lowest Southern Hemisphere sea ice extent seen in the satellite record (1979 to present) and coincided with anomalously warm surface waters surrounding most of Antarctica. We use this event as an example to discuss the mechanisms that are important for linkages between tropical climate variability and climate in the Southern Hemisphere high latitudes. Specifically, we show that two distinct processes contributed to this event: First, the extreme El Niño event peaking in December–February 2015/2016 contributed to pronounced extratropical SH sea surface temperature and sea ice extent anomalies in the eastern Ross, Amundsen, and Bellingshausen Seas that persisted in part until the following 2016 austral spring. Second, internal unforced atmospheric variability of the Southern Annular Mode promoted the exceptional low sea ice extent in November–December 2016. These results suggest that a combination of tropically forced and internal Southern Hemisphere atmospheric variability contributed to the unprecedented sea ice decline during the 2016 austral spring, on top of a background of slow changes expected from greenhouse gas and ozone forcing. We argue that models need to capture both ocean-atmosphere coupling in the pan-tropics as well as ocean-atmosphere-sea-ice interactions in the Southern Ocean accurately to be able to simulate events such as this.