I just dug into the on watch menu on my Garmin 255M. Under the WiFi it shows that it's connected to my home network. There's the option to look for networks . If I select that it scans for other available networks and I can see my other home network ( and a few of the neighbours) If I then select my other home network it prompts for the password. If I switch networks it remembers the passwords of the networks that I have previously logged in to.