To clarify:
Phone - with no internet, CAN connect to F800 Pro's wi-fi. (This is to use the mobile app to view/manage your F800 Pro, you'd go into your phones wi-fi and search for "Thinkware ____")
F800 Pro CAN NOT connect to a phone's wi-fi hotspot if the phone does not have an internet connection. (This is to be able to use cloud functionality which requires internet access, this you'd set up your internet hotspot details within the Thinkware app)
So depending on what you meant exactly... but at the end of the day, the internet is not required to access your F800 Pro; only for cloud access.