Cellphones do not require an Internet connection in order to send or receive calls, texts and multimedia messages. In order to use apps that require an Internet connection such as Facebook, YouTube or Instagram, a mobile data or Wi-Fi connection is necessary.
Smartphones powered by operating systems like Android, iOS and Windows do not need an Internet connection for functions that do not require the sending of data over the Internet. Many games and productivity applications do not require a data connection to use and function the same whether or not an Internet connection is available. Wi-Fi hotspots and mobile data networks provide Internet connectivity to mobile devices by radio transmission through the air.