Southern right whale vocalizations were recorded concurrently with visual observations off the sub-Antarctic Island of South Georgia, and the characteristics of these calls were described. Calls were also compared to those of humpback whales at South Georgia, to determine how the two species might reliably be distinguished acoustically. The southern right whale calls measured (which were all upcalls) had lower frequency with peak energy and were mostly shorter in duration than the calls measured from humpback whales. The frequency upsweep and the lack of harmonics of southern right whale calls were also diagnostic characteristics.