Which Assassin's Creed game introduced the series' naval exploration and ship combat?

Assassin's Creed III introduced the series' naval exploration and ship combat.

Released in 2012, Assassin's Creed III added naval missions in which players command the ship Aquila. These sequences involve steering, sailing, positioning the vessel, and firing broadside cannons during battles. The feature became popular enough to inspire the larger maritime focus of Assassin's Creed IV: Black Flag.

The game is primarily set during the American Revolution, with Connor Kenway as its main historical protagonist. Earlier games included water travel and occasional sea scenes, but Assassin's Creed III was the entry that established dedicated naval gameplay as a major series feature. Black Flag expanded that system into open-world Caribbean exploration, rather than introducing naval combat for the first time.