Settings > Security and Privacy > More security settings > SIM card security > Toggle on 'Lock SIM card' > Follow on-screen instructions from here. It may ask for a ...

Protect yourself against SIM swapping and more security threats by setting up a SIM PIN right now.

If you've just got your hands on a shiny new Sim card, congratulations. Switching your Sim (the chip that dictates your allowance) can unlock huge savings. Now comes the crucial step of activating it ...