If you wish to play the game on an emulator, the most legitimate method is to of the game from your physical 3DS cartridge. Intellectual Property & Piracy FAQ - Nintendo Support
Downloading a for a 3DS emulator is a complex topic that involves both technical steps and important legal considerations regarding copyright. Legal Considerations Detective Pikachu ROM Download For 3DS Emulator
: Emulators themselves, such as Citra or its successors like Azahar , are generally considered legal as they are original software and do not contain proprietary Nintendo code. How to Play Detective Pikachu on an Emulator If you wish to play the game on
: Nintendo explicitly states that the uploading and downloading of its game files, commonly called "ROMs," is illegal . How to Play Detective Pikachu on an Emulator
: While U.S. copyright law (17 U.S.C. section 117) may allow users to create a backup copy of a program they legally own for personal use, this generally does not extend to downloading a second copy from the internet.