South Flat is an unincorporated community in Washakie County, Wyoming, United States.

As of the census[1] of 2000, there were 374 people, 133 households, and 109 families residing in the CDP.

There were 133 households, out of which 41.4% had children under the age of 18 living with them, 69.9% were married couples living together, 4.5% had a female householder with no husband present, and 18.0% were non-families.

15.8% of all households were made up of individuals, and 7.5% had someone living alone who was 65 years of age or older.

Public education in the community of South Flat is provided by Washakie County School District #1.