The Great South Bay Bridge is a bridge on the southwest side of Suffolk County, New York, on Long Island. It connects the Robert Moses Causeway from Long Island's mainland over the Great South Bay, connecting to both Captree and Jones Beach Island. It serves as access via the Robert Moses Causeway to both of the downstream crossings, the State Boat Channel Bridge and the Fire Island Inlet Bridge, also leading visitors and on-lookers to either the Fire Island Lighthouse or the Robert Moses State Park.