SWITCHING

How to Switch Mobile Network Without Losing Your Number (2026 Guide)

Switching UK mobile networks is straightforward when you know the steps — from checking coverage on your new network to requesting a PAC code and avoiding hidden exit charges.

Updated 2026-06-14 · 6 min read · NetScan UK

KEY TAKEAWAYS

Text PAC to 65075 (free) from your current SIM to receive your Porting Authorisation Code within 60 seconds — this works on every UK network and MVNO.
The PAC code response includes details of any early termination fee you may face — calculate the full switching cost before deciding to switch mid-contract.
Your old contract closes automatically when the number port completes — you do not need to separately cancel with your old provider.
The number port must complete within one working day under Ofcom rules — in practice, many ports complete within a few hours.
Always verify coverage on your new network before switching — check netscanai.co.uk/#scan and buy a trial SIM to confirm real-world performance at your address.
If you want to leave without keeping your number, text STAC to 75075 instead — this terminates your old contract without porting the number.

Switching mobile networks in the UK is one of those tasks that feels complicated until you do it once, after which it seems obvious. The mechanics are simple: you request a Porting Authorisation Code (PAC) from your current provider, give it to your new provider, and your number moves across within one working day. The complications most people worry about — losing their number, extended downtime, being charged exit fees they did not expect — are either avoidable with a few minutes of preparation or less severe than anticipated.

The more important decision is usually the one before the actual switch: choosing which network to move to. A switch that takes you from a network with good signal at your address to one with weak signal is not a win, regardless of how much you save per month. Coverage should be the first thing you verify, not an afterthought. Use NetScan UK's free postcode scanner at netscanai.co.uk/#scan to rank all four UK networks at your home and work postcodes before you begin the switching process.

This guide is a practical, step-by-step walkthrough of the entire UK network switching process — from coverage verification through to the moment your number is live on the new network. We also cover the less obvious questions: what happens to your old contract, when early termination fees apply, how to time a switch to minimise disruption, and what to do if something goes wrong.

Step 1: Verify Coverage on Your New Network Before You Switch

The single most important step before switching is confirming that the network you are moving to covers your home address, your workplace and your regular commute better than — or at least as well as — your current network. Coverage varies enormously between postcodes, and the network that everyone in your office uses may not be the right choice for your address. Run your postcodes through NetScan UK at netscanai.co.uk/#scan for an immediate Ofcom-based ranking of all four networks at your locations.

Cross-reference with the new network's own coverage map, paying attention to the indoor coverage prediction — not just outdoor signal. If you work from home in an older property, indoor coverage is the metric that determines whether calls drop and data stalls in your most-used location. If possible, buy a cheap SIM from your intended new network and test it for a week before committing. A brief trial period is the only way to confirm that predicted coverage translates to real-world performance at your specific address.

Step 2: Request Your PAC Code

Once you have confirmed coverage on the new network, request your PAC code from your current provider. The fastest method: text the word PAC to 65075 from the mobile number you want to transfer. This free text works on every UK network and MVNO. Your current provider must respond within 60 seconds with your nine-character PAC code, along with details of your contract end date and any early termination fee that would apply if you switch now.

Read the contract information in the PAC response carefully. If you are still within a minimum contract term — for example, 14 months into a 24-month handset deal — you may face an early termination fee equal to the remaining monthly payments. Sometimes the savings from a better new deal outweigh the exit fee; calculate both before deciding whether to switch now or wait until the contract ends. If you are on a rolling monthly plan, there should be no exit fee and switching becomes a pure comparison between current and new monthly cost.

Step 3: Sign Up with Your New Provider and Hand Over the PAC Code

When you sign up for your new SIM or plan, you will be asked whether you want to keep your existing number. Select yes and enter your PAC code when prompted. If you are signing up online, there is usually a dedicated field for this during the activation process. If you are signing up in-store, the member of staff will take the PAC code and enter it on your behalf. You will also need to specify a preferred switch date — typically the next working day for online sign-ups, though some providers offer same-day porting.

At this point, your new SIM will arrive (or your eSIM will be downloadable) in advance of the port completing. The SIM will be assigned a temporary number initially. On the day the port completes, your existing number transfers across and the temporary number is retired. Keep your old SIM active and in your device until the port is confirmed complete — you do not need to do anything else to make this happen.

Step 4: The Switch Day — What to Expect

On the agreed switch day, there will be a brief period — typically measured in minutes — when your old SIM stops working and before your new SIM activates with your ported number. This is the standard porting window mandated by Ofcom to be as short as possible. You will usually receive a text or notification from your new provider confirming the port is complete. After that confirmation, your number is live on the new network and your old SIM is deactivated.

If you have not yet received your new SIM by switch day, contact your new provider immediately to delay the port until the SIM arrives. Completing a port without a ready SIM will leave you temporarily without a usable mobile number. Assuming your SIM or eSIM is ready, ensure it is inserted in (or downloaded to) your device before switch day. Remove your old SIM afterwards — it will no longer work once the port completes.

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Frequently Asked Questions

How do I switch mobile network without losing my number in the UK?

Text PAC to 65075 from the SIM you want to keep. Your current provider will reply within 60 seconds with a nine-character Porting Authorisation Code. Give this code to your new network during sign-up, and your number will transfer across within one working day. Your old contract terminates automatically when the port completes.

Will I lose my phone number when switching networks?

No — that is precisely what the PAC code system prevents. Using a PAC code transfers your existing number to the new network, so all calls, texts and services tied to your number continue uninterrupted. Only the network behind your number changes; the number itself stays the same.

Do I need to cancel my old contract before switching?

No. When your new provider processes the PAC code and the number port completes, your old contract is automatically terminated. You do not need to separately cancel with your old network. If you are mid-contract, an early termination fee may apply — the details are included in the text you receive when you request your PAC code.

How long does it take to switch networks and keep my number?

Under Ofcom rules, the port must complete within one working day of your new provider submitting the request. Many ports complete within a few hours. There is a brief period of downtime — typically a few minutes — when your old SIM deactivates and before the new SIM activates with your number. Choose a working day for your switch, and submit the PAC code early in the day for the fastest possible turnaround.

Can I switch to an MVNO and keep my number?

Yes, the PAC code porting process is identical whether you are switching between main networks, from a main network to an MVNO, between MVNOs, or from an MVNO to a main network. Text PAC to 65075, get your code, give it to the new provider, and the number transfers across.

What if I want to leave my current network but don't care about keeping my number?

Text STAC to 75075 instead of PAC to 65075. STAC stands for Service Termination Authorisation Code. Your provider must respond within 60 seconds. Using the STAC code with your new provider triggers the closure of your old account without porting the number — you will receive a new number from your new provider.

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