Co-op in Splatoon Raiders can be played locally or online.
Local play uses nearby systems through local wireless, allowing players in the same physical area to cooperate without relying on an internet match. Online play extends the same idea to friends or other players connected through Nintendo’s network services. In either case, the activity remains cooperative: players work together through raids instead of fighting each other in competitive matches.
Up to four players can participate, so an individual playing alone can bring in up to three additional players. The game’s official descriptions distinguish local wireless from online play; this is not the same as split-screen-only multiplayer, and it does not require an amiibo or any postal feature.
The distinction is useful for readers comparing Raiders with mainline Splatoon modes. Raiders is primarily a single-player adventure, but its campaign-oriented missions are designed to accommodate both solo progression and group play. Local and online options therefore describe two ways to access the same cooperative side of the game.