Which Assassin's Creed game first introduced naval gameplay to the main series?

Assassin's Creed III first introduced naval gameplay to the main Assassin's Creed series.

Released in 2012, Assassin's Creed III includes missions in which the player commands the ship Aquila. These sequences take place during the American Revolutionary War and involve sailing, maneuvering, and firing cannons against enemy vessels. Naval missions were integrated into the broader campaign rather than forming the entire game.

The feature became much more prominent in Assassin's Creed IV: Black Flag, released in 2013. Black Flag made ship exploration, sea battles, and piracy central to its structure, which is why many players remember it as the game's defining naval entry. Its protagonist is Edward Kenway, a Welsh privateer and pirate.

Assassin's Creed Rogue also built heavily on naval exploration, but it followed Black Flag. Thus, Black Flag popularized the system, while Assassin's Creed III introduced it to the main series.