South Bay, FL has a population of 5,026 and is the 6,451st largest city in the United States. The population density is 1,872 per sq mi which is 538% higher than the Florida average and 1966% higher than the national average. The median age in South Bay is 37 which is approximately 12% lower than the Florida average of 42. In South Bay, 22% of the population over 15 years of age are married, 76% speak English and 21% speak Spanish. 57% of South Bay residents were born in Florida, 23% were born out of state, 2% were born outside of the United States and 18% were foreign born.