Keeping Your Number

If you've decided that you'd be happier using a different network or contract, you can switch services AND keep your existing mobile number. This is termed 'Number Portability' when you take your number from one mobile phone network to another, and 'Number Migration' when you take your number from one contract to another within the same network.

Keeping Your Number on a New Handset

If you are staying with your network provider, and are simply changing your handset,there are two things that you need to be aware of:

1. SIM Cards

Your SIM card contains your mobile phone number and all the details of your subscription - your phone's identity. If you take out the SIM card from one handset and put it into another, it should mean that you have moved your mobile number and bills to the new handset.

However, some networks (such as Orange) put software in all their phones to stop you using any other network's SIM in them. This SIM lock (or SP lock) can be removed by the network, although they will charge you to do this. You may be able to unlock your phone through a third party company, either by sending your phone to them, or simply obtaining a release code. Do beware though, using a third party company may invalidate your phone warranty.

Vodafone PAYG phones may not only be locked to Vodafone, but may also be locked so that they won't accept any other SIM card. Again, a third-party company may be able to resolve this problem.

2. Phone Compatibility

Vodafone and O2 mostly operate on a frequency of 900Mhz, whilst Orange and T-mobile operate at1800MHz. All new phones should work on both these frequencies (dual-band), so changing phones should not be a problem, unless you're changing to an older model.

Moving Your Number to a New Service

Firstly, make sure that you do not cancel your old service. The number you want to transfer must be active during the week or two it takes to move it to the new account or network. Suspended numbers have to be re-activated by your old service provider before any transfer can take place.

1. Request a PAC

Ask your current service provider for a nine-character Porting Authorising Code (PAC). This is the evidence your new provider needs to confirm that your current provider has released you. Providing you have no outstanding debts, and are outside your contractual obligations to your existing network provider, then you should be given a PAC reference within 2 working days of your request. However, if you are still within the contract period, then you will need to pay the remainder of the line rental before they will release you.

2. Inform Your Provider

When moving network, you should let your dealer or provider know at the outset. You will either need to inform them or your new network of your PAC details. The table below explains what action you need to take when transferring to a particular network service.