Up to four people can play Pokémon Pokopia together in online or local wireless multiplayer.
The multiplayer mode lets players visit shared building spaces and create a Pokémon settlement with friends. Nintendo describes both online play and local wireless play as supporting a maximum of four participants, so the number applies to either of those multiplayer options.
This limit is separate from the game's single-player mode, which remains the main way to experience the story and restoration journey. It is also different from GameShare, a feature that can allow another person to try the game during a shared session even without owning a copy.
Local wireless multiplayer has additional requirements: Nintendo states that each player needs a compatible console and a copy of the software. Online play requires Nintendo Switch Online features. The four-player ceiling is therefore a mode limit, not a claim that only four Pokémon can live in a player's wider settlement.