is a city in Duval County, Florida, United States. When the majority of communities in Duval County consolidated with Jacksonville, Florida in 1968, Atlantic Beach, along with Jacksonville Beach, Neptune Beach, and Baldwin, Florida, remained quasi-independent. Like the other towns, it maintains its own municipal government but its residents vote in the Jacksonville mayoral election and have representation on the Jacksonville city council. The population was 13,368 at the 2000 census. According to the U.S Census estimates of 2005, the city had a population of 13,436.
Atlantic Beach took off around 1900 after Henry Flagler built the Mayport stop of his East Coast Railway to the north of the town. The Atlantic Beach Corporation bought and developed most of the land in what is now Atlantic Beach in 1915, and the town was incorporated in 1926.
The current mayor is John Meserve, who is also the manager of Fleet Landing, a veteran's retirement community in the town.
According to the United States Census Bureau, the city has a total area of 33.6 km² (13.0 mi²). 9.7 km² (3.7 mi²) of it is land and 24.0 km² (9.2 mi²) of it (71.26%) is water.