Which studio led development of Assassin's Creed IV: Black Flag?

Ubisoft Montreal led development of Assassin's Creed IV: Black Flag.

The Montreal studio developed Black Flag with support from several other Ubisoft teams. The project expanded the naval gameplay introduced in Assassin's Creed III and made sailing, exploration, piracy, and ship combat central parts of the experience.

Black Flag was released in 2013 for PlayStation 3, Xbox 360, Wii U, Windows, PlayStation 4, and Xbox One. Its historical story follows Edward Kenway, a Welsh privateer who becomes involved with both pirates and the Assassin-Templar conflict.

Other Ubisoft studios contributed to different Assassin's Creed games and supporting work, which can cause confusion about the lead developer. Ubisoft Quebec later led major projects including Assassin's Creed Odyssey, while Ubisoft Singapore became especially associated with naval development.