Yes it will. Whichever size of SIM card your existing phone or tablet takes, a O2 three-in-one SIM card will fit. Just pop out the size you need, either standard, micro or nano, and place it into your tablet or phone.

Yes you can. Just follow the steps below:

Make sure you can switch network: Check with your existing network to make sure there are no cancellation charges if you switch to O2. These cancellation charges will usually apply if you are still within the contract time length of your current contract.

Choose your new O2 SIM Only deal: Keeping your existing mobile phone and taking out a O2 SIM Only contract is a great way of saving money, in some cases it could half your current monthly cost. We have lots of O2 SIM Only deals for you to choose from.

Get a Porting Authorisation Code (PAC code): Once you have decided to leave your exisitng network and choosen your new O2 SIM Only deal, you need to call your existing network and ask them for a PAC Code. If you phone your existing network up, Ofcom have insisted that they have to give you your PAC Code immedialety. At this stage your network may try to tempt you to stay with them, offering you a better deal.

Give your PAC code to your new network: If your existing network has been unable to tempt you to stay with them, call up O2 and give them the PAC Code you got from your exisitng network, once you have given O2 your PAC Code, it usually take 24 hours for your mobile phone number to be switched.

4G comes as standard on all O2 purchases. You'll get great coverage too. O2 has promised Ofcom that 98% of the UK population can get calls, texts and 4G data, both indoors and out by the end of 2017. A recent Ofcom survey found that 86% of O2 customes are satisfied with the coverage they get. The best satisfaction results of all networks.

Check O2's signal strength in your area with the ofcom network checker.