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Mobile Number Porting (MNP)

All major mobile phone networks in the UK will allow you to transfer (or to use the correct terminology ´port´) an existing phone number over to their service when taking out a new contract. This is guaranteed by Ofcom´s General Conditions of Entitlement that all mobile phone operators are bound by. However, each network provider, and also many mobile phone retailers, will have their own number porting rules that you should be aware of.

Retailers and network operators will provide information regarding their number porting rules on their websites. When ordering a new phone online you should double-check this information if you intend to keep an old number as there is a great deal of variation from retailer to retailer about how this service is implemented. There are usually less restrictions for porting a number to or from a PAYG phone than for contract phones.

PAC Code

In order to transfer a phone number from one network provider to another you will need to request a Port Authorisation Code (PAC). This code is issued by your existing network and then used by your new provider to transfer your number over. Once requested the PAC code lasts for 30 days, after which it expires and a new PAC code must be requested. The Port Authorisation Code is also known as the Porting Authorisation Code. PAC code and PAC number mean the same thing.

Many network providers will assume that by requesting a PAC code you wish to cancel your contract with them, even if you do not use the code after your request. This has a number of repercussions. Firstly, if you request a PAC code and then decide to stick with your existing contract you may find yourself without a usable phone.

Secondly, if you are in a minimum term contract (e.g. 12, 18, 24 or 36 months) you will need to request your PAC code after the final month of the contract has begun. For example, you should request a PAC code after 11 months of a 12 month contract have elapsed. You can request a PAC code earlier than this, but this will inevitably mean that you are breaking your contract early.

Although your network provider may provide you with a PAC code at any point during your contract there may be financial repercussions for doing this before your minimum term has ended. They may charge you a termination fee (´disconnection penalty´) and you will still be expected to pay for the remainder of the contract, possibly upfront. If you have fulfilled your contractual obligations the PAC code is usually provided for free and you are under no obligation to reveal your reasons for requesting the PAC code.

How you will receive your PAC code

Your PAC Code can be provided in various ways. It might be given to you over the phone, sent via SMS or email or delivered in the post. The way in which you receive your PAC Code will depend on which network you are requesting it from. Your network operator must provide you with a PAC code within 2 days of you requesting one, or provide a reason why they are unable to do so. If you have still not received your PAC code 48 hours after your initial request you can phone your current network provider and demand that they give it to you over the phone.

Update - From April 11 2011 Ofcom will change its rules regarding number porting. Under the new rules network operators will be obliged to provide the PAC code within two hours of a request being made. The PAC code must be supplied either by phone or SMS message. The new rules will forbid network operators from posting PAC codes by mail, which can cause significant delays in the transfer of mobile phone numbers.

Porting or Upgrading

PAC codes are generally only issued for moving from one network provider to another. A network operator will not issue a PAC code for moving from one contract to another on their service as this is classed as an upgrade. In order to keep your existing phone number with a new contract tariff or handset on the same network you will need to negotiate an upgrade with your network provider. You will not require a PAC code to do this. This may pose a problem if you find a new contract through a third-party retailer on the same network as it might not be possible to transfer your number in such circumstances.

The one exception to this rule seems to be when transferring to an O2 iPhone contract from any other O2 contract, in which case O2 will allow you to keep your existing phone number by requesting a PAC code. This should also apply when opting for the O2 iPhone through a third-party retailer although it is recommended that you confirm this with your chosen retailer before purchase.

When to Provide Your PAC

While you will need to provide your PAC code to your new service provider to port your phone number over there are different rules on when to do this. Some networks and retailers will require you to provide your PAC Code during the purchase process while others will allow you to do so for a short period after the start of your new contract. Some network operators, such as T-Mobile, will allow you to port a phone number over at any point during your contract.

During the purchase Process

When you need to provide a PAC code during the purchase process you should request a PAC code from your existing network provider before you begin. This can take a number of days, particularly if the PAC code is delivered by mail. When placing your order you will be asked to enter your PAC code if you wish to transfer the old number over.

When you are required to enter the PAC code during the purchase process you will generally not be allowed to do so after your order has been completed. Because of this you should be sure of your chosen retailer´s rules on number porting if you wish to keep an existing number. If you fail to provide a PAC code during the order process you will have missed your opportunity to port your existing number over.

After your order is completed

Retailers that allow you to provide a PAC code after your order is completed offer you a bit more flexibility but in many cases there may still be a limited period during which you can do so. When purchasing from such retailers you should still make yourself aware of their number porting rules before purchase to provide yourself with plenty of leeway. As it can take time to receive your PAC code and some retailers may only provide you with a few days to port your number it is advisable to have your PAC code ready to ensure that everything goes smoothly.

Before placing an order for a new mobile phone check what number porting rules apply for your chosen network operator or retailer if you wish to keep an old number. You will not be able to port a phone number from a contract that has expired or been terminated and is no longer in use.


Different retailers have different agreements in place with the various UK networks, so while some retailers will allow you to port your number to and from any network others may only be able to offer this service for specific networks. For example, one retailer may allow you to port your phone number to a new Orange, O2 or T-Mobile phone but not to a new 3 Mobile, Vodafone or Virgin contract.

To complicate matters further there may be different rules in place for each network with the same retailer. So while you may be able to port your number over to Orange after your order has been completed, the same retailer may restrict you to porting your number to O2 or T-Mobile during the purchase process and not allow you to do so later. Because of this it is essential that you check your individual retailer´s specific rules regarding number portability.

Porting from PAYG

You do not need to currently be on a contract in order to keep your existing number as you are still able to request a PAC code for Pay As You Go (PAYG) phones. One thing to bear in mind is that when transferring a phone number from a PAYG phone to a contract you may lose any credit currently on the PAYG phone. Some network operators may transfer this credit over to your new phone but others may not, so check their individual rules if you have a large amount of credit on your existing PAYG handset. If you are unable to transfer this credit you should use it up before the date your phone number is due to be ported otherwise it will be lost.

Porting to PAYG

Retailers that only stock PAYG phones may not provide information regarding number porting. Porting a phone number to a PAYG phone should generally not be a problem as you will not be required to do so during the order process and there will not usually be a limited time period to do this. As long as you have an active PAYG SIM card (or request a new SIM from your chosen network) there should be no restrictions on transferring a number over. The only difficulty you may encounter is when you attempt to port a phone number from a contract phone that has yet to expire.

Your Existing Contract

As mentioned earlier you cannot port a disconnected number. This means that you should not cancel your existing contract until you have successfully ported your number to your new phone, otherwise you will permanently lose that phone number.

In most instances porting a phone number will be viewed as a request to terminate an existing contract and so this will happen after your number has been successfully transferred. In many cases merely requesting a PAC code will be viewed as a desire to terminate your contract, whether that PAC code is used or not. That being said, there are a number of network providers that will not terminate your contract when a PAC code has been requested or a number has been ported.

Your Existing SIM Card

When your phone number has been ported from your old SIM card to your new SIM card you may lose access to your existing SIM card. What this means is that any personal information such as saved SMS messages or phone numbers may be irretrievably lost. Before you start the porting process make sure you back up any information you wish to retain after your number has been successfully ported. You can try and save this information directly to your phone, or to be on the safe side copy them down to a piece of paper.

Transfer Period

During the porting process any phone calls made to your phone number may be ´lost´. You will not receive them and may receive no indication that they were made. People attempting to phone this number during the porting process may receive a ´number not recognised´ message. SMS messages sent to your phone number during this process may also be lost, although in some instances they may be delivered to your new handset/SIM card.

Some final things to remember

  • Check your chosen retailers rules on number porting before placing your order
  • Make sure you are aware of when you need to provide a PAC code
  • Make sure you have your PAC code ready for when you need it
  • Check whether you need to provide a PAC during purchase. If this is the case you will not be able to do so later
  • Make sure your current contract has expired or is in its final month before requesting a PAC
  • Use any credit remaining on your phone as this will not be transferable
  • Backup any important information stored on your existing SIM card

The most important thing to remember is that each retailer will have their own rules regarding number porting, and that these rules may differ for each network with the same retailer.