St. Augustine South is a census-designated place (CDP) in St. Johns County, Florida, United States.

[3] It is part of the Jacksonville, Florida Metropolitan Statistical Area.

[4] According to the United States Census Bureau, the CDP has a total area of 1.7 square miles (4.5 km2), all land.

There were 1,993 housing units at an average density of 1,158.7 per square mile (447.4/km2).

The racial makeup of the CDP was 96.80% White, 0.95% African American, 0.26% Native American, 1.11% Asian, 0.02% Pacific Islander, 0.14% from other races, and 0.71% from two or more races.