Getting a new pay monthly phone does not mean losing your mobile number or risking unexpected charges. In the UK, you can switch networks, keep your number using a PAC code, or cancel your contract with a STAC code.
This guide explains how switching works for pay monthly contracts, how to check your contract status, and what to do before upgrading or moving to a new network. If you already know you want to move, you can compare pay monthly deals across every network we list before requesting a code.
Reviewed by Phil Brown, founder of Mobile Phone Finder. Phil has worked in the UK mobile industry, including retail management at Three UK, and has spent over a decade building consumer technology comparison platforms. About the author
Check your pay monthly contract before switching
Before switching networks or taking out a new pay monthly phone, it is important to understand your current contract.
Check whether you are still within your minimum term, whether early termination charges apply, and whether your handset is being paid for separately from your airtime.
If you leave a pay monthly contract early, you may be charged the remaining monthly fees. If your minimum term has ended, you are usually free to switch without penalties, although your contract may continue on a rolling basis until you cancel.
You can normally find these details in your online network account, on recent bills, or by contacting your network directly. There is also a faster way to check, explained in the next section.
Check your exit cost first with an INFO code
If you want to know where you stand before committing to anything, text INFO to 85075 from the mobile number in question.
Your network must reply with your contract end date and any early termination charges that would apply. Requesting this information does not start a switch, does not cancel anything, and does not commit you to leaving.
This is the step most people skip. Knowing the exit cost before you start makes it far easier to judge whether switching now is worthwhile or whether waiting until your minimum term ends is the better decision.
How to keep your number when switching networks (PAC code)
If you want to keep your mobile number when switching networks, you will need a PAC code, also known as a Porting Authorisation Code. This allows your existing number to be transferred to a new network.
A PAC code is valid for 30 days and should only be requested when you are ready to switch.
In the UK, you can request a PAC code by texting PAC to 65075 from your mobile phone. The text is free, and your network must reply within one minute. That reply must include the code itself along with details of any early termination charges that apply.
Some networks may also ask you to confirm personal details, such as your date of birth, before issuing the code.
Once you have your PAC code, you give it to your new network when taking out your new pay monthly contract. This can usually be done during the order process or after your new phone or SIM has arrived. Your number is usually transferred within one working day.
Texting for a code works for a single number. If you are moving more than one number, such as a family account, you will normally need to request the codes through your network account online, through its app, or by phoning your network.
What is a STAC code and when should you use one?
A STAC code, or Service Termination Authorisation Code, is used when you want to leave your network without keeping your number.
You might use a STAC code if you no longer want your current number, if you are cancelling your contract without switching immediately, or if you are moving to a different type of service.
To request a STAC code, text STAC to 75075. Once a STAC code is used, your contract will be cancelled automatically. Unlike PAC codes, STAC codes are designed to end service rather than transfer a number.
You will still owe any early termination charges if you are inside your minimum term, along with any outstanding handset balance and usage up to the switch date. You should not be charged for a notice period running after the switch, which is explained below.
You should not pay two networks at once
Before 2019 it was common to be charged a notice period by your old network that ran on after you had already moved, meaning you paid two providers for the same weeks.
Ofcom banned that practice in July 2019, at the same time as introducing text-to-switch. Your old network can still charge you for the remainder of your minimum term if you leave early, and for what you have used up to the switch date, but it cannot add a notice period on top that runs past the day you move.
If a final bill appears to charge you beyond the switch date, it is worth querying it with your old network and referring to the Ofcom rules on notice period charges.
Switching after a mid-contract price rise
Most UK networks now increase prices once a year, and the amount and timing vary considerably between them. Those increases are set out in your contract terms before you sign, so an increase you were told about is not usually grounds to leave without charge.
Where a provider changes terms in a way you were not told about at the point of sale, the position can be different. In 2026, O2 raised its annual airtime increase above the amount previously written into customer contracts, and affected customers were given the right to exit without an early termination charge, although any outstanding handset balance remained payable.
If your network announces an increase that does not match what you agreed to, check whether it has offered a penalty-free exit window before assuming you are locked in. Our network pages set out the current price rise position for each provider, including O2, Three, Vodafone and Tesco Mobile.
Some providers avoid annual increases altogether. Talkmobile no longer applies annual price rises, and Mozillion states that its pay monthly pricing is fixed for the contract term. If a rising bill is what prompted you to look at switching, those are worth comparing.
How to check when your pay monthly contract ends
Knowing when your pay monthly contract ends can help you avoid unnecessary charges and make switching easier.
The quickest method is the INFO code described above. You can also check by logging into your network account online, reviewing your monthly bill, or contacting customer support.
If your minimum term has ended, you are free to upgrade, switch, or cancel. Monthly payments may continue until you actively cancel. If you are still in contract, your network must tell you about any early exit fees when it issues a PAC, STAC or INFO reply.
How switching options affect your next phone
When it is time to get a new phone on a pay monthly contract, your switching choice affects how the process works.
- Upgrade with your current network: this usually lets you keep your number automatically and move onto a new contract.
- Switch networks and keep your number: use a PAC code when taking out a new pay monthly deal.
- Switch networks without keeping your number: use a STAC code, cancelling your contract and starting fresh with a new provider.
Each option has different costs and implications depending on whether you are still in contract and whether your handset is fully paid off.
Coverage is worth checking before price. Several providers run on another network's masts rather than their own, so switching between them will not change the signal you get. If you want to compare what is available before you commit, you can compare pay monthly deals across networks and retailers, or see which providers use which network on our networks pages.
Common pay monthly switching mistakes to avoid
Most problems when switching pay monthly contracts are avoidable. Common mistakes include:
- Cancelling your contract before requesting a PAC code.
- Letting a PAC code expire before using it.
- Not checking for early termination fees, when an INFO code would have told you.
- Switching mid billing cycle without understanding final charges.
- Moving to a provider that runs on the same network you are leaving, when the reason for switching was poor coverage.
Taking a few minutes to check your contract details can prevent delays and unexpected costs.
Things networks do not always make clear
Some details are easy to miss when switching pay monthly contracts.
- Number transfers usually happen on working days only.
- Weekend switches can be delayed.
- Final bills often include pro rata charges or remaining handset balances, even if your number has already moved.
- Discounts or loyalty benefits may end as soon as a PAC or STAC code is issued, not when the switch completes.
- Your network is not allowed to refuse you a code, even if you owe money. It may offer you a deal to stay, and you are free to decline.
Understanding these points helps avoid surprises during the switching process.
Frequently asked questions
Will switching pay monthly networks affect my credit score?
Taking out a new pay monthly contract usually involves a credit check. Switching networks itself does not negatively affect your credit score.
How long does it take to transfer my number?
Once you give your PAC code to your new network, number transfers usually complete within one working day.
Can I switch if I am still paying off my phone?
Yes, but the handset balance still has to be settled. How that works depends on your contract. Where the handset and airtime are separate agreements, the handset credit agreement continues or must be paid off, while the airtime moves with you. Where they are combined, you will usually need to settle the outstanding amount. Check which structure you are on before requesting a code.
Can I find out what leaving would cost without starting a switch?
Yes. Text INFO to 85075 and your network must reply with your contract end date and any early termination charges. Requesting this does not begin a switch or cancel anything.
Will I be charged a notice period by my old network?
No. Ofcom banned notice period charges running after the switch date in July 2019. You can still be charged for the remainder of your minimum term if you leave early, and for usage up to the switch date, but not for a notice period after you have moved.
Can my network refuse to give me a PAC code?
No. Your network must issue the code within the time limits Ofcom sets, even if you owe early termination charges or have an outstanding handset balance. It may offer you a retention deal when you request it, and you are under no obligation to accept.
Summary
Switching to a new pay monthly phone is usually straightforward once you understand your contract status and whether you need a PAC or STAC code.
Checking the details first helps you keep your number, avoid unnecessary charges, and move to a new contract with confidence. If you are unsure where you stand, an INFO code costs nothing and starts nothing.
If you are deciding what to buy next, you can also browse mobile phones to shortlist models before you switch.
How we put this guide together
The switching process described here is set by Ofcom rather than by individual networks, so the rules on codes, timings, notice periods and what providers must tell you are taken from Ofcom's published switching guidance and its General Conditions rather than from network marketing pages.
Where individual networks differ, such as annual price rise policies, we have said so and linked to the relevant network page rather than generalising across the market. We do not test switching times ourselves, and the timings given are the regulated maximums that providers must meet.
Sources and methodology
- Ofcom guidance on switching mobile provider, for PAC, STAC and INFO codes, the short codes used to request them, and the rules on what providers must tell you
- Ofcom statement on text-to-switch reforms, effective 1 July 2019, for the ban on notice period charges running after the switch date and the one minute reply requirement
- Ofcom General Conditions, for provider obligations on issuing codes, timings for single and multiple number requests, and switching information requirements
- Ofcom statement on O2 price rises, for the 2026 increase and the penalty-free exit offered to affected customers
Switching rules and network policies change. Confirm current conditions with Ofcom or your provider before acting on anything in this guide.
