The scene of Pokémon Sun and Pokémon Moon is the Alola region, which comprises four tropical islands and one artificial island. Many never-before-seen Pokémon populate the lush islands of Alola. The story begins shortly after the main character moves to Alola. Once players have decided whether they want to play as boys or girls, they can choose their name and appearance. Hardly arrived, their adventure begins, during which they will meet many fascinating people. The Pokédex is a useful tool that records information about the Pokémon that the player sees and catches during their adventure. In Pokémon Sun and Pokémon Moon, Professor Kukui gives the player a very special Pokédex called the Rotom Pokédex. It houses a Rotom, a Pokémon that can penetrate into electrical devices. The Rotom Pokédex can register much more than just Pokémon; it has its own personality. It shows the player on the map where they are and where they must go next, and it also gives clues to the next goal based on conversations with other characters.

In Pokémon Sun and Pokémon Moon, there is a feature called the QR Code Scanner that allows players to obtain information about a Pokémon by reading the QR code for that Pokémon. This enables them to register the Pokémon of the Alola region in their Pokédex and find out where their habitats are. If players read the QR code of a Pokémon they haven't caught yet, they can locate it this way. Pokémon Sun differs from Pokémon Moon in the Pokémon players can encounter during the game and the frequency with which they appear. Only Pokémon Sun and Moon are compatible with each other in terms of combat and trade opportunities. This game is not compatible with Pokémon accessories or other Pokémon players.