Mile-long beach near Downtown with wetlands, a boardwalk, hiking trails, picnic areas & concessions. Virginia Key is an 863-acre barrier island in Miami, Florida, United States in Biscayne Bay, south of Brickell and north of Key Biscayne. It is accessible from the mainland via the Rickenbacker Causeway. The island is mainly occupied by the Virginia Key Beach Park, Miami Seaquarium, Miami-Dade's Central District Wastewater Treatment Plant, and the University of Miami Rosenstiel School of Marine and Atmospheric Science. Other facilities include the former Miami Marine Stadium, the National Marine Fisheries Service Southeast Fisheries Science Center, and an office of the U.S. National Oceanic and Atmospheric Administration.