Due to UK/EU anti-fraud regulations (PSD2), O2 requires a verified identity for international calling. If you bought a SIM from a vending machine, international calling is blocked until you register your ID online or in-store. You aren't removing a technical bar; you are removing a KYC (Know Your Customer) hold.
Here is the deep technical and procedural dive into how to dismantle that barrier. Before we get into the codes, let’s understand the why . O2, like all Mobile Network Operators (MNOs), is terrified of three things: Premium Rate Fraud, SIM Swapping exploits, and Bill Shock. how to remove international call barring - o2
You get the freedom of dialing out, without the risk of a £400 bill because your pocket dialed a number in the Maldives. Removing O2’s international call barring is a battle of three fronts: the GSMA star codes ( #33# ), the app spend management (My O2), and the network’s credit policy. Start with ##002# and escalate to a human using SS7 terminology. The line is open; you just have to tell the exchange to let you cross it. Due to UK/EU anti-fraud regulations (PSD2), O2 requires