Fort Walton Beach, often referred to by the initialism FWB, is a city in southern Okaloosa County, Florida, United States. As of the 2020 U.S. census, the population was 20,922, up from 19,507 in 2010. It is a principal city of the Crestview−Fort Walton Beach−Destin, Florida Metropolitan Statistical Area. Fort Walton Beach is a year-round fishing and beach resort community. Its busiest time of the year is the summer, causing a boost to the local economy because of seasonal human migration.