I have configured my Fenix3 and Garmin express to use my home WiFi Network.
Is it possible to have multiple WiFi networks configured on the device/application?
I would be happy to help you with this. You can configure WiFi networks in another location through Garmin Express. Since the Fenix wouldn't be able to detect a WiFi in another location you will have to manually enter the Wifi Network Name(SSID) and Password in Garmin Express.
Launch Garmin Express
Select the device
Select Tools
Select Utilities
Select Add a Network
Select + Add a Network Manually
Enter the Network Name
Select the type of Security and enter the Password if needed
Click Save
When entering the network's information, capitalization matters and the Network Name and Password must be exact.