TL;DR:
- Getting a new mobile number in the UK requires a free STAC code, which the provider must deliver within one minute. The switch completes within one working day if the process is followed correctly, with timing being crucial to avoid service gaps. Both individuals and businesses benefit from choosing memorable numbers and timing switches during weekdays to ensure a seamless transition.
Getting a new mobile number in the UK means using a Service Termination Authorisation Code (STAC) to leave your current network and start fresh with a new number. This is the official Ofcom-regulated process, and it is faster than most people expect. Providers must reply to your STAC request within one minute, and the full switch completes within one working day. Whether you are a sole trader wanting a dedicated work line or an individual who simply wants a clean break, the process is the same. Phonenumbers makes finding the right 07 mobile number straightforward before you even begin.
What do you need before getting a new mobile number?
Preparation prevents delays. Before you request a STAC code or register a new mobile line, three things must be in order: your handset, your contract status, and your personal details.
Device readiness
Your phone must be unlocked to accept a SIM from a different network. Since december 2021, Ofcom required UK networks to sell all new handsets unlocked by default. If you bought your phone before that date, contact your current provider to request an unlock. Most do this free of charge, though it can take a few days to process.
Contract and billing checks
Check whether you are inside a minimum term contract. Changing your mobile number via STAC ends your old contract, and early termination fees may apply. When you text STAC to 75075, the reply includes your early termination charges, handset balance, final bill date, and any pay-as-you-go credit remaining. That reply arrives within one minute, giving you all the financial information you need before committing.
What to have ready
| Prerequisite | Why it matters |
|---|---|
| Unlocked handset | Required to activate a new SIM on a different network |
| Current account number | Needed to verify identity with your new provider |
| Photo ID | Standard identity check when registering a new mobile line |
| Direct debit or payment details | Required to set up your new contract or pay-as-you-go plan |
| Knowledge of early termination fees | Helps you decide whether to switch now or wait |
Pro Tip: Check your contract end date via your provider’s app before texting STAC. If you are within two months of the end date, waiting could save you a significant early exit fee.
How do you get a new mobile number step by step?
The UK’s Text-to-Switch system puts you in control. You do not need to call your provider or sit through a retention pitch. The STAC code process is free, and providers cannot refuse to issue one under Ofcom rules.
Here is the full process from start to finish:
- Text STAC to 75075 from your current mobile. This is a free text and works on any UK network.
- Receive your STAC code. Your provider must reply within one minute. The message includes your STAC code, any early termination charges, your handset balance, your final bill date, and any pay-as-you-go credit.
- Review the charges. Read the reply carefully before proceeding. If the fees are acceptable, continue. If not, you can wait until your contract ends.
- Choose your new provider and number. Select the network and tariff that suits you. If you want a memorable 07 number rather than a randomly assigned one, browse Phonenumbers’ UK mobile number selection options before signing up.
- Give your STAC code to the new provider. Do this when completing your sign-up. The STAC code is valid for 30 days, so you have time to shop around.
- Wait for the switch to complete. The new network completes the switch within one working day of receiving your STAC. You do not need to do anything else.
- Swap your SIM card. Only swap to the new SIM once you receive confirmation that the switch is complete. Swapping too early can cause a temporary loss of service.
- Confirm your new number works. Make a test call and send a test message. Update your contacts, email signature, and any business listings with your new contact number.
Pro Tip: Your STAC code expires after 30 days. If you do not use it within that window, simply text STAC to 75075 again to get a fresh one at no cost.
One critical point: do not cancel your old contract yourself. The new provider handles termination automatically once you hand over the STAC code. Cancelling manually can disrupt the process and cause billing complications.
What timing mistakes should you avoid when switching?
Timing your switch poorly is the most common reason people experience service gaps. The rules are straightforward once you know them.
Switching on a Friday or over the weekend means your switch will not complete until the following Tuesday at the earliest. Ofcom’s one-working-day rule only counts business days, so a Friday request effectively means a four-day wait. For anyone relying on their mobile for work, that gap is costly.
Weekend switch requests push completion to the next available working day. A Monday or Tuesday request is the safest option. It gives the switch time to complete well before the weekend, and you have working hours available if anything needs resolving with your new provider.
Pro Tip: If you have an important call, interview, or client meeting later in the week, wait until it has passed before initiating your switch. Even a smooth switch can cause a brief period of no service while the SIM activates.
Other timing pitfalls to avoid:
- Do not swap your new SIM into your phone before the switch confirmation arrives. The old SIM must remain active until the process is complete.
- Do not initiate a switch during a period of travel abroad. International roaming can complicate activation.
- Do not ignore the 30-day expiry on your STAC code. If it lapses, you must request a new one, which resets the clock on any planned switch date.
Initiating your switch early in the working week is the single most effective way to avoid downtime. Professionals who depend on uninterrupted communication should treat this as a fixed rule, not a suggestion.
How does a new number benefit individuals and businesses differently?
The reasons for changing your mobile number vary significantly between personal users and business owners. Both groups benefit, but in different ways.
For individuals
- Privacy and a fresh start. A new number cuts ties with unwanted contacts, spam callers, and old social circles. This is particularly useful after a change in personal circumstances.
- Avoiding emergency contact confusion. If your old number is listed as an emergency contact in schools, GP surgeries, or with family, update those records before the switch completes.
- Simplicity. A new number is often easier than trying to block or filter an old one that has been widely shared.
For UK businesses and sole traders
- Dedicated work line. A dedicated business mobile number helps UK sole traders maintain clear boundaries between work and personal communication.
- Tax legitimacy. A separate business number makes it straightforward to claim mobile costs as a business expense.
- Professional image. Clients and customers respond differently to a dedicated business number than to a personal mobile. It signals that you take your work seriously.
- Dual-SIM convenience. Modern iPhones and Samsung Galaxy phones support dual-SIM functionality, meaning you can run a personal and business number on one device without carrying two phones.
For businesses, the number portability process deserves careful planning. Updating your number across your website, Google Business Profile, invoices, and marketing materials takes time. Build that into your switch timeline.
Key takeaways
Getting a new mobile number in the UK requires a STAC code, a working-day switch window, and careful timing to avoid service gaps.
| Point | Details |
|---|---|
| Use STAC, not a phone call | Text STAC to 75075 to get your code free within one minute, no retention call needed. |
| Switch completes in one working day | Ofcom mandates completion within one working day of your new provider receiving the STAC. |
| Never cancel your old contract yourself | Hand the STAC to your new provider and let them handle termination automatically. |
| Avoid Friday switches | Weekend requests delay completion until Tuesday, creating unnecessary downtime. |
| Businesses benefit from a dedicated number | A separate business line supports tax claims, professional image, and work-life boundaries. |
My honest view on switching mobile numbers in the UK
The STAC process is genuinely one of the better-regulated consumer systems in UK telecoms. Ofcom’s one-minute response rule and the one-working-day completion window are enforced, and providers cannot stall or refuse. That is not the case in every country.
What I find most people get wrong is the timing. They initiate a switch on a Thursday afternoon, panic when nothing has happened by Friday evening, and assume something has gone wrong. Nothing has gone wrong. They just did not account for working days. Starting on a Monday removes that anxiety entirely.
The other thing worth saying clearly: a randomly assigned number from a new network is fine for personal use, but it is a missed opportunity for a business. A memorable 07 number is not just easier for clients to recall. It signals permanence. When a customer sees the same number on your invoice, your website, and your van, they trust you more. That trust has real commercial value, and it costs very little to get right from the start.
Dual-SIM phones have also changed the calculation for sole traders. Carrying two devices used to be the only way to keep work and personal calls separate. Now, one phone handles both lines cleanly. If you have not explored that option, it is worth doing before you commit to a new contract.
— Rob
Finding your ideal UK mobile number with Phonenumbers
Phonenumbers is the UK’s leading provider of memorable 07 mobile numbers, alongside 01 and 02 landline numbers. Once you have your STAC code and are ready to register a new mobile line, the number you choose matters.
Phonenumbers lets you search by number sequence, area code, or town, so you can find a number that is genuinely easy to remember and share. Numbers are no longer tied to local areas, meaning you can use any UK number anywhere in the country. Whether you want a number for a new business or simply a personal line that is easy to give out, Phonenumbers has a wide selection ready to activate. Visit phonenumbers.store to browse available 07 numbers today.
FAQ
What is a STAC code and how do I get one?
A STAC (Service Termination Authorisation Code) is the code you need to leave your current mobile network and get a new number. Text STAC to 75075 from your current phone and your provider must reply within one minute, free of charge.
How long does it take to get a new mobile number?
Once your new provider receives your STAC code, the switch completes within one working day under Ofcom rules. Avoid submitting on a Friday to prevent weekend delays.
Can I change my phone number for free?
Requesting a STAC code is free under Ofcom regulations, and providers cannot charge for issuing one. Early termination fees from your existing contract may still apply depending on your remaining term.
Should I cancel my old contract before switching?
No. Hand your STAC code to the new provider and they handle the termination automatically. Cancelling your old contract yourself can disrupt the process and cause billing issues.
Can I use a new number for business without a second phone?
Yes. Most modern smartphones, including iPhones and Samsung Galaxy models, support dual-SIM functionality. This lets you run a personal and business number on one device without carrying two handsets.
