The principal open-world setting of Assassin's Creed IV: Black Flag is the Caribbean Sea.
The game follows Edward Kenway, a Welsh privateer who becomes involved with both pirates and the Assassin-Templar conflict during the Golden Age of Piracy. Its open world connects islands and coastal cities across the Caribbean.
Important locations include Havana, Kingston, Nassau, and a variety of smaller islands and settlements. Naval travel is central to the game, with Edward commanding the ship Jackdaw and engaging in exploration, trade, boarding actions, and sea battles.
Black Flag is sometimes described simply as a Caribbean pirate game, but its historical period and fictional conspiracy remain part of the wider Assassin's Creed narrative. It is also distinct from the Mediterranean settings emphasized by several earlier entries.