A Garmin Messenger user posted on Reddit that they installed the app on a second phone, entered their number, typed in the text code and watched their old conversations come back, with no Garmin password asked for. The second phone could also send and receive new messages, and they found no way to see or sign out other phones, Gadgets & Wearables reported on October 27. It was the user's own number, so nothing leaked, but carriers hand abandoned numbers to new people, and Messenger chats can hold check-ins, travel plans and shared locations.
Garmin Support told the user the app works as designed and that the findings would be reviewed, and DC Rainmaker said Garmin had passed them to the right team, Android Authority reports. Garmin hasn't said whether a new owner of a number would see the old owner's chats. Uninstalling the app doesn't unlink your number, so if you're changing numbers, open Messenger and go to Accounts, then Manage Garmin Messenger Account, then Delete Garmin Messenger Account. Garmin says that removes the number without cancelling your inReach subscription.