Up to three other players can visit another player in Pokémon Pokopia’s multiplayer mode.
That means a session can include the host and three visitors, for a maximum group of four players. Visitors can spend time together in the host’s world and each can bring a Pokémon along.
Pokopia supports visits through local wireless and online play. The game also includes GameShare, which can allow a friend who does not own the game to participate under the stated system and session requirements. These features extend the game’s social-simulation focus beyond a purely single-player building experience.
The number three refers to visiting players, not the total number of people in the session. Saying “four” describes the maximum total group, while “three” is the precise answer to the question as worded. This distinction helps avoid a common counting mix-up.