Pokemon Let’s Go, the new game for the Nintendo Switch, does not require that you own or have played Pokemon Go on mobile devices. While Pokemon Let’s Go on Switch does draw some comparison to Pokemon GO on mobile, the two games are completely separate things. However, there is some functionality between the two games that Pokemon Go players will have when playing the game.
Quick Answer: No
If you do have a Pokemon collection in Pokemon GO on mobile devices you can transfer those Pokemon to Let’s Go on the Switch. This functionality actually doesn’t open up until later in the main story of Pokemon Let’s Go. After players reach Fuchsia City in Pokemon Let’s Go they will unlock the ability to transfer Pokemon from Pokemon Go to Pokemon Let’s Go.
To do this you will need to open the application on your phone and head into the settings menu. You’ll need to connect your mobile device to your Nintendo Switch and open the game on the console. In Pokemon Let’s Go you can then head into the options menu and open the Pokemon Go settings to sync your accounts.
Following the successful connection you can transfer Pokemon from Pokemon Go to Pokemon Let’s Go. You cannot transfer from Let’s Go to Pokemon Go and you cannot send back or cancel any transfers that you make between the devices.
Fuchsia City is the main hub for transferring Pokemon at the Go Park building. The attendant at the Go Park location will have a menu that gives you the option to bring Pokemon to Pokemon Let’s Go which will finish the transfer process. Completing this transfer you will need to actually catch this Pokemon to put him in your collection. Just walk up to them like any other Pokemon in the game and play the ball mini-game to get the Pokemon Go Pokemon into your Let’s Go Pokemon party.