Ingenico payment terminals can still operate without a SIM card by using alternative connectivity options such as Wi-Fi or Ethernet. If the terminal supports these connection types, you can connect to the internet or your payment processor's network through a Wi-Fi or wired Ethernet connection. This allows you to process payments without the need for a mobile network. For businesses operating in areas with no reliable internet connection, a wired setup or local network connection may be ideal for ensuring secure payment processing without a SIM card.