The supported range
The official FAQ gives Big Walk a 2–12 player range, and the Nintendo listing provides the same online party context. Two is the minimum supported group and twelve is the maximum stated in the collected material. That answers the headline question without needing to invent a preferred party size.
What 2, 3 and 4+ mean
When the host creates a world, the game offers versions tuned for two players, three players or four-plus players. These choices describe the intended shape of the world rather than changing the overall maximum from twelve. A group should pick the variant that matches the party it expects to use for that session.
Small groups
Two players make each observation and decision more visible because there are fewer voices and positions in the world. That can be useful for a focused route, but it does not make two the official best size. The source set confirms the format, not a ranking of how much fun each group size must be.
Large groups
A larger party creates more chances for someone to notice a clue or test a tool, while also creating more noise and more distance to manage. Players should call out discoveries, agree on a regroup point and avoid assuming that every person heard the same explanation. These are practical communication habits, not official difficulty ratings.
Host responsibility
The host starts the world, chooses the party variant and owns the save. That makes the host a more important planning role than simply being the person who clicks Create. Agree on a reliable host before the group invests in a route, and read the save-progress page before the next session.
Joining across platforms
The official FAQ confirms cross-platform play, so the group does not need to use the same version to reach the same world. Use the platform friend route where possible, then a current Join Code if the session does not appear. Crossplay expands the available group; it does not add random matchmaking.
The practical recommendation
Choose the smallest group that can meet consistently and communicate clearly. If the group grows, use the 4+ world variant and keep the host and session route stable. If someone wants to play alone, explain that the official game format starts at two and no single-player mode is listed.