Pokémon GO developer Niantic has announced plans to officially roll out account linking with Facebook, in addition to a number of login updates. The complete announcement from the development team is as follows:
Facebook Account Linking and Login Updates Coming to Pokémon GO!
Good news, Trainers! We’ll soon begin rolling out support for account linking with Facebook. Along with a simpler sign-in process, linking Pokémon GO to your Facebook account gives you more options to log in and helps preserve your progress across devices.
With this change, you will also be able to link your Trainer profile to your Facebook and Google accounts, and use any of those credentials to access Pokémon GO. For example, someone who currently logs in with Pokémon Trainer Club could link their Trainer profile to both their Google and Facebook accounts, and then they can use whichever account they prefer going forward. To link your Trainer profile to a Google or Facebook account, access the Settings menu and then select the platform you’d like to link.
Account linking is especially useful for someone who has registered for Pokémon GO using a Google Account that they may not be able to access in the future, such as one associated with a work or university email address. By linking their Facebook account, they can continue to make progress on their Pokédex, and even link a new Google account to their Trainer profile.
Please note: this feature will only be available to Trainers aged 13 and over.
For details about this new feature, visit the Pokémon GO Help Center. We hope you enjoy this new way to enter the world of Pokémon GO!
—The Pokémon GO team
Source: Official Pokémon GO blog