An O2 pay as you go SIM card now gives you more freedom than ever! Top up and use your credit like normal. or get more with a data pack. Why choose an O2 PAYG SIM? No contract. no credit check Top up like normal or choose a data pack O2 Rewards and access to O2 Priority Roll over your unused data to the next month Roaming in European Zone included WiFi calling included Access to O2 PriorityO2 Priority is a free exclusive to O2 customers and bringing great offers from high street brands. unique prize draws to unforgettable moments. invite-only access to gigs. perks and experiences. How to use your new O2 SIM card:1. Order your PAYG SIM2. All SIM cards come in 3 different sizes and will fit almost all handsets. so just select the correct size and insert the SIM into your phone once it arrives3. Once inserted. you�ll need to wait for your service to go live. You�ll know that your service is live when you see the signal bars appear at the top right of your phone screen4. Top up your account or purchase one of O2�s data packs. You can do this using the My O2 app or call 4444 from your O2 mobile