Based on museum and stranding records, leatherback turtles (Dermochelys coriacea) were previously considered a rare migrant in South Carolina nearshore waters with only 9 recorded prior to 1980. In 1989, leatherback sightings increased, both alive and dead, in large numbers. From 1980 to 2003, 141 leatherback carcasses stranded. These leatherback strandings were highly seasonal, with a major peak in spring and a minor peak in fall. Based on 23 necropsies, there were 7 males and 16 females (1:2.3). From 1994 to 2003, during April–June, 1131 live leatherbacks (0.04 per km) were observed during 50 nearshore aerial surveys flown parallel to the South Carolina coast. The highest concentration during a single flight was in May 2002, with 175 leatherbacks seen over 605 km of transect line or 0.29 per km. Leatherbacks were not randomly or uniformly distributed, but had a contagious (clumped) distribution. Numbers observed varied significantly between inner and outer transect lines, among years, and among flights within a year. These lines of evidence demonstrate the recent occurrence, spatial distribution, and temporal variability of leatherbacks in South Carolina nearshore waters.