If you previously purchased the game, you can still redownload it for the foreseeable future by visiting the "Redownloadable Software" section in your eShop settings.
The official digital file size for on the Nintendo 3DS is approximately 3.2 GB (26,215 blocks). While some online sources may list slightly smaller file sizes around 3.0 GB or 3.1 GB for various region-specific versions or modified files, the standard download version typically requires a 4 GB SD card to accommodate the full game and save data. Important: Availability of Digital Downloads Download Pokemon Sun (EU) | 3DS File | 3.1G
Since digital purchases are no longer available, the primary legal way to play is through physical retail copies: If you previously purchased the game, you can
Downloading unauthorized "3DS files" or ROMs from unofficial third-party sites is illegal and carries risks. Historically, Nintendo has issued permanent hardware bans to users caught using pirated copies of Pokémon Sun online, which blocks the console from all Nintendo network services, including the eShop and online play. Legitimate Ways to Play Pokémon Sun As of , the Nintendo 3DS eShop has officially closed
You can no longer purchase digital copies of Pokémon Sun directly from the official store.
As of , the Nintendo 3DS eShop has officially closed .
Pokémon Sun And Moon's download size is over 3 gigabytes - Vooks