Mobile data is one of the major ways to get internet when there is no WiFi. You can purchase a mobile data plan from various carriers, such as AT&T and Verizon. Hence, you simply have to turn on your device's cellular data connection to access the Internet. Obviously, this only works for devices with dedicated SIM slots, such as smartphones and tablets. PC users, however, can connect to the internet using Ethernet when there is no WiFi. They can also use USB tethering or Bluetooth tethering.