Migration assistant within the Fitbit app / Source – Google
When the Pixel Watch launched last year, a Google account was not required for Fitbit because Google account migration had not yet begun. Both Google and Fitbit accounts still work on the original Pixel Watch as well as other devices that use Fitbit features, that is until the 2025 cutoff previously announced.
Once you’ve done all that, your Fitbit account will be linked with Google and you will be able to use your Fitbit devices and services as usual. However, you will need to use your Google account to log in to the Fitbit app and website.