With O2 you can choose from Pay Monthly or Pay As You Go sim card only deals.
Please Click Here for the full range of Sim Only Plans from O2.
Please Click Here for the full range of Pay Monthly Sim Only Plans from O2.
Please Click Here for the full range of Pay & Go Sim Only Plans from O2.
A pay monthly sim only plan is perfect if you're happy with your current mobile phone (tablet) and just need a tariff. You get all the benefits of O2 without having to change anything and your monthly bill is cheaper.
Depending on your device and location, you may be able to get 4G speeds. But don't worry if you can't, as you'll still be able to use 3G on O2's sim only price plans.