Circumnavigation of Manhattan became possible in 1905 with the construction of the Harlem Ship Canal, the first regularly scheduled trip being the Tourist captained by John Roberts in 1908.

On June 15, 1945, Frank Barry, Joe Moran and other partners merged several companies to form Circle-Line Sightseeing Yachts, offering boat tours of New York operating out of Battery Park.

Among the items cited in the transfer was a newer fleet (although Hornblower would have to buy the Circle Line boats) and the possibility of new service to Gateway National Recreation Area.

Approximately 20 years later current Mayor Mike Bloomberg proclaimed September 17 "Circle Line Sightseeing Cruises Day" in 2008.

758 participated in several landings during the Pacific Theater of World War II, including those during the battles of Leyte, Ormoc Bay, Mindoro, and Lingayen Gulf.