Shared Horizons.

The Australian Nintendo store page for Animal Crossing: New Horizons has revealed important details regarding the island and player limits for this title:[1]

  • "Up to 8 players with registered accounts on a Nintendo Switch console can live on one shared island."

  • "Up to four residents of one island can play simultaneously on one console."

  • "Only one island can exist per Nintendo Switch console, irrespective of the number of user accounts registered to or copies of the game used on one console."

  • "One Nintendo Switch and one copy of the game is required for each unique island. Alternatively, up to eight people can play together on one island via local wireless or online play."

  • "Local wireless play requires one console and one copy of the software per player."

  • "Internet connection required during online play. To use online services, you must create a Nintendo Account and accept the related agreement. The Nintendo Account Privacy Policy applies. Some online services may not be available in all countries. Online play requires paid online membership."

Considering the Switch is supposed to function as a family console that allows each user to have their own save file, the one island per Switch limit is disappointing.

Sources:

  1. "Animal Crossing: New Horizons." Nintendo.com.au. Retrieved January 31, 2020.