Switching mobile network in the UK has never been simpler, yet millions of customers stay on expensive contracts because they assume changing provider means losing their phone number. It doesn't. Since Ofcom overhauled the switching process, you can keep your existing mobile number by requesting a short code known as a PAC — a Porting Authorisation Code — and handing it to your new provider. The whole port typically completes within one working day, and your old contract is cancelled automatically once the switch goes through. If you have ever wondered how to switch mobile network without the hassle, this guide walks you through every step.
Why does it matter right now? Competition among UK networks and MVNOs is fierce, and staying on an old deal can mean paying more than the offers available to new customers elsewhere. A PAC code lets you move to a cheaper or better-coverage plan while keeping the number your contacts, bank and two-factor authentication apps already know. There is no charge for requesting a PAC, and Ofcom rules mean your old provider cannot refuse to give you one.
Before you jump, the single most important decision is choosing the right network for your location. The UK has four physical mobile networks — EE (owned by BT), Vodafone, O2 (part of Virgin Media O2) and Three — and every other brand is a virtual operator (MVNO) riding on one of those four sets of masts. EE offers the widest geographic and rural coverage and serves as the backbone of the Emergency Services Network. Vodafone and O2 generally come next in overall reach, while Three tends to be fast for data but has the thinnest rural and indoor footprint. Your experience will depend heavily on your postcode.
Throughout this guide we will explain how the PAC process works step by step, and highlight pitfalls to avoid. We strongly recommend running your postcode through NetScan UK's coverage scanner at netscanai.co.uk/#scan before committing — it ranks all four host networks for your area using Ofcom premises data, so you can see exactly which operator gives you the best signal at home, at work and on your commute.
What Is a PAC Code and How Does It Work?
A PAC code (Porting Authorisation Code) is a nine-character alphanumeric code issued by your current mobile provider. It authorises the transfer of your phone number from one network to another. Once you give the PAC to your new provider, they initiate the port, and — under Ofcom regulations — the switch must complete within one working day. At the moment the port goes live, your old SIM stops working, your new SIM activates with your existing number, and your previous contract is automatically cancelled. You do not need to contact your old provider to cancel separately.
It is worth knowing the difference between a PAC and a STAC. A PAC is what you need if you want to keep your number. A STAC (Service Termination Authorisation Code) is used when you want to leave your provider but do not wish to take your number with you — for instance, if you are closing a secondary SIM. Both are free to request and both trigger automatic cancellation, but only the PAC preserves your mobile number. For the vast majority of switchers, the PAC is the code you want.
PAC codes are valid for 30 days from the date of issue. If you do not use yours within that window, it simply expires and your existing contract continues as normal — nothing changes. This means there is zero risk in requesting one: you can get your PAC, shop around for deals, and only commit when you are ready. Your current provider is legally required to send the PAC via text within one minute of your request.
Step-by-Step: How to Get a PAC Code and Switch
Step 1 — Check coverage at your new network. Before anything else, verify that the network you are considering actually provides strong coverage where you need it. Use NetScan UK's postcode scanner at netscanai.co.uk/#scan to compare all four host networks side by side, then cross-reference with the operator's own coverage map. Remember that 'population coverage' figures (often quoted in adverts) reflect where people live, not total land area — if you spend time in rural areas, geographic coverage is what matters, and EE generally leads on that front.
Step 2 — Request your PAC. The quickest method is to text PAC to 65075 from the mobile number you want to port. Your current provider must reply within one minute with your nine-character PAC code and key contract information, including any early-termination charges. Alternatively, you can call your provider or log in to their app or website. You do not have to give a reason for leaving, and the provider cannot refuse your request or add delays.
Step 3 — Choose your new plan and give the PAC to your new provider. When you sign up for your new SIM-only or handset contract, there will be an option to enter a PAC code. Provide the code exactly as received. Your new provider will coordinate the port with your old one.
Step 4 — Wait for the switch. The port will complete within one working day of your new provider submitting the request. You will usually receive a text on your new SIM confirming the number has transferred. Insert the new SIM (or activate the eSIM) and you are done. Your old contract is cancelled automatically, though you may receive a final bill for any outstanding charges or early-termination fees.
Other Ways to Get Your PAC, Network by Network
The text to 65075 works on every UK network and every provider that runs on one. If you would rather not text, each network has its own routes as well. EE customers can call 150 from their EE phone or use the EE app. Three customers can call 333 or use the Three app. Vodafone customers can call 191 or use the My Vodafone app. O2 customers can call 202 or use the My O2 app. Low-cost providers usually offer the code in the online account or app.
On a business or multi-line account, the account holder may have to make the request, and the text route may not be available for every line. Ask the provider's business team.
If you are moving between two providers on the same host network, for example from giffgaff to Tesco Mobile, which both use O2, the PAC still moves your number. Your coverage will not change, though, because the masts are the same. If poor signal is your reason for leaving, make sure the new provider runs on a different network.
Order the new SIM before you use the code. If the new SIM has not arrived by the day the number is due to move, contact the new provider and ask them to hold the transfer until it does. A number that has moved to a SIM you do not have yet leaves you without service.
Choosing the Right Network: MNOs and MVNOs Explained
Every mobile plan in the UK ultimately runs on one of four physical networks: EE, Vodafone, O2 or Three. The MVNOs (Mobile Virtual Network Operators) lease capacity from these host networks, so your coverage and signal experience is determined by the underlying infrastructure, not the brand on the SIM. For example, giffgaff and Tesco Mobile both use O2's masts; SMARTY and iD Mobile run on Three; VOXI and Lebara use Vodafone; and 1pMobile operates on EE. If O2 has poor coverage at your postcode, giffgaff will too — and vice versa.
MVNOs often undercut the host network's own prices because they have lower marketing and retail overheads. 1pMobile runs on EE, SMARTY and iD Mobile on Three, giffgaff on O2, and Talkmobile on Vodafone. Plan prices change often, so check the provider's own site for today's price — and remember the four networks also sell plans directly, so it is always worth comparing both.
If you need unlimited data, compare the unlimited tiers on the networks that cover you — prices change often, so verify on the provider's site before you commit. The key takeaway is that switching network does not have to be expensive — many MVNO deals are rolling monthly contracts with no lock-in, making them ideal landing spots after a PAC-code switch.
What About Early-Termination Fees and Contract End Dates?
If you are still within a minimum-term contract (typically 12 or 24 months), your current provider may charge an early-termination fee (ETF) when you switch. This is usually calculated as the remaining monthly payments left on your contract, sometimes with a small discount applied. When you text PAC to 65075, the provider is required to include details of any ETF in their reply, so you will know the exact cost before you decide to proceed.
In many cases, switching makes financial sense even with an ETF. If the monthly saving on your new plan is greater than the ETF spread over the remaining months, you come out ahead. Do the maths carefully. If your contract is close to ending, it may be worth waiting a few weeks until you are out of the minimum term, at which point you can leave with no penalty. Once your minimum term expires, most contracts roll into a 30-day arrangement, giving you complete flexibility to switch whenever you like.
One common concern is device payments. If your current deal bundles a handset, the outstanding device balance is separate from the airtime contract. Ofcom rules require providers to split these clearly. You will need to settle any remaining device payments, but this does not prevent you from getting a PAC or porting your number. Check your latest bill or app dashboard to see exactly what you owe.
Common PAC Code Pitfalls and How to Avoid Them
The biggest mistake people make is switching to a network without checking local coverage first. It is easy to be seduced by a headline price, only to discover the host network barely reaches your home or workplace. Always check your postcode — NetScan UK's scanner at netscanai.co.uk/#scan uses Ofcom Connected Nations premises data to rank the four networks for your specific location. EE generally leads in rural and geographic coverage, but in some urban areas O2, Vodafone or Three may be just as strong or stronger. There is no single 'best' network — only the best network for where you actually use your phone.
Another pitfall is letting your PAC expire and assuming the process is over. The PAC is valid for 30 days; if it lapses, you will need to request a new one. Similarly, some customers accidentally request a STAC instead of a PAC, which terminates the contract without porting the number — meaning you lose the number permanently. Always text PAC (not STAC) to 65075 if you want to keep your number.
Watch out for providers who try to persuade you to stay by offering retention deals. There is nothing wrong with accepting a good counter-offer, but be aware that the provider is required to give you the PAC promptly regardless of any sales pitch. If you feel pressured, simply insist on the code or use the text method, which bypasses any call-centre retention scripts entirely. Finally, remember that porting happens on working days — if you submit your PAC on a Friday afternoon, the switch may not complete until Monday.
After the Switch: What to Check and How to Verify Coverage
Once your number has ported and your new SIM is active, take a few minutes to confirm everything is working. Send a test text, make a call and check mobile data. If you use Wi-Fi calling or VoLTE (Voice over LTE), you may need to enable these in your phone's settings — not every MVNO supports them, so check your new provider's help pages. Also update any apps that use your phone number for verification, such as WhatsApp or banking apps; although your number has not changed, some services detect a SIM swap and require re-authentication.
Coverage can feel different even on the same host network if your new MVNO does not have exactly the same roaming or spectrum agreements. In practice, the difference is usually negligible, but if you notice weaker signal in certain spots, make sure your phone's network settings are set to automatic and that you have the latest carrier configuration update installed. If coverage is genuinely poor, remember that most MVNO SIM-only plans are rolling monthly — you can switch again with a new PAC at any time without penalty.
We also recommend revisiting your coverage expectations every year or so. The UK networks are continuously expanding 4G and 5G infrastructure, and Ofcom's Connected Nations reports (published annually) track these improvements. A network that was weak at your postcode last year may have improved, and vice versa. Keeping an eye on NetScan UK's postcode scanner means you will always know whether a better option has emerged for your area.