The sea ice surface, not open water, is the dominant source of sea salt to aerosol and ice cores in coastal Antarctica. Here, we show that it may also form the dominant source for central Antarctica. We can then explain higher concentrations in the winter and last glacial maximum (LGM) as being due to increased sea ice production. This suggests that ice core sea salt can indicate at least the timing of changes in Antarctic sea ice production. The pattern of sea salt in ice cores is consistent with marine evidence about sea ice changes in the Holocene and LGM. Sea salt shows no change at the initial CO2 increase out of the last glacial, making it unlikely this was primarily due to changing sea ice cover. The sea salt record should not be treated as an indicator of meridional transport.