TL;DR
- Text PAC to 65075 on your current network to get a Porting Authorisation Code for taking your number to a new network; text STAC to the same number if you are happy to leave without your number.
- Your current operator must provide the PAC or STAC by text within one minute (or by other means within two hours) and cannot charge you for it.
- Once you give your PAC to your new operator, the switch completes within one working day.
- Check coverage, contract terms, and any outstanding ETF on your current contract before initiating the switch.
- You do not need to contact your current provider to tell them you are leaving; the PAC/STAC process handles the switch automatically.
The text-to-switch system explained
Ofcom introduced the text-to-switch system in July 2019, fundamentally simplifying how consumers and small businesses switch mobile network in the UK. Prior to that date, switching with your number required contacting your existing operator, requesting a PAC, and then separately contacting the new operator - a process that could take days and involved operators attempting to retain customers. Under the current rules, the entire switching process is initiated by a single text message, and your existing provider has no right to obstruct or delay it.
The system uses two codes. A Porting Authorisation Code (PAC) is for customers who want to take their existing mobile number to the new network. A Service Termination Authorisation Code (STAC) is for customers who are happy to leave their current number behind - for example, those starting fresh with a new number on the new network. Both codes are obtained by texting the relevant keyword to 65075 from the number you want to switch or cancel. There is no charge for obtaining either code, and your operator is legally required to provide it.
PAC codes: keeping your number when switching
Number portability is a right under Ofcom's General Conditions. Your mobile number does not belong to your operator - it is allocated to you as a subscriber, and you can take it with you when you change provider. To port your number, text PAC to 65075. Your operator must send you the code by text within one minute. If they cannot do so within one minute (for example, due to technical issues), they must provide it by another means within two hours. The code is valid for 30 days.
Take the PAC to your new operator - either online, in store, or over the phone - and they will manage the porting process. Once you have provided the PAC to your new operator, the switch completes within one working day. During the brief porting window, your service may be unavailable for up to a couple of hours. Your old contract is terminated as part of the porting process; if you are still within your minimum term and no ETF waiver applies, you may receive a final bill from your old operator covering any remaining ETF and outstanding charges.
STAC codes and leaving without your number
If keeping your number is not important, you can use a STAC instead. Texting STAC to 65075 generates a Service Termination Authorisation Code, which tells your old operator to cancel your account and close your number. You take out a new contract with a new operator and receive a new mobile number. The same one-minute response rule applies, and the code is again valid for 30 days. This route is common for people who are moving abroad, who have separate work and personal numbers and are rationalising, or who simply are indifferent to retaining their existing number.
Using a STAC still triggers the termination of your old contract. If you are outside your minimum term, cancellation is free. If you are within the minimum term, the ETF rules apply in the same way as they do for a PAC port. The STAC process does not exempt you from outstanding financial obligations under your existing contract - it simply manages the technical and administrative process of leaving.
What to check before switching
Before texting for a PAC or STAC, it is worth conducting a short due-diligence checklist. First, establish whether you are within your minimum contract term, and if so, what the approximate ETF would be. Ofcom rules cap ETFs and require them to reflect only the operator's genuine loss, but a mid-contract switch with a sizeable ETF can offset the savings from a cheaper deal on a new network. Second, check coverage for your regular locations on the prospective new network using Ofcom's checker and the operator's own tool - a cheaper tariff is no benefit if the coverage is materially worse.
Third, review what your current operator might offer to retain you. Operators cannot prevent you from switching, but you are under no obligation to tell them you are leaving before you request a PAC or STAC. In practice, the moment you text for a PAC, your operator will typically text back with the code alongside a retention offer. You are free to evaluate that offer, decline it, and proceed with the switch - or accept it if it represents better value. There is no obligation to make a courtesy call before switching.
| Switch type | Text to send | Number to text | Code valid for | Switch completes |
|---|---|---|---|---|
| Keep existing number (port) | PAC | 65075 | 30 days | Within 1 working day of giving PAC to new operator |
| Leave without number | STAC | 65075 | 30 days | On the date agreed with new operator |
| Check current switching status | INFO | 65075 | N/A | N/A — returns account information |
Timelines and what happens during the switch
Once you provide your PAC to your new operator, number porting completes within one working day under Ofcom's rules. The period of service interruption during the actual port is typically brief - often a matter of hours during the early morning or overnight. Your new SIM becomes active on your new network and your old account is closed. If you have an eSIM-capable device, some operators can provision a new eSIM profile remotely, avoiding any physical SIM exchange, though you should confirm the new operator's eSIM support and process before relying on this.
After the switch, you should receive a final bill from your old operator. Review it carefully against any ETF calculation you made before switching and cross-check that no unexpected charges have been applied. Any billing disputes with the old operator are subject to the same complaint process as any other billing issue - raise them in writing within a reasonable period of receiving the final bill, keeping records of all correspondence.
What this means in practice
Daniel is on a 24-month SIM-only contract that expired three months ago. He has been paying £28 per month on a rolling basis since. He has seen an equivalent data allowance on a different network at £18 per month for a 12-month contract. He texts PAC to 65075 at 9:15am on a Tuesday. Within 45 seconds he receives his PAC by text, alongside a brief retention message from his current operator offering a reduced rate. He compares the retention offer against the new deal, finds the new deal is still better, and provides the PAC to the new operator online that afternoon. By Wednesday morning his number has ported, his new SIM is active, and his old account is closed. His final bill from the old operator arrives by email covering his usage up to the porting date only, with no ETF since he was out of contract. He saves £10 per month, or £120 over the new 12-month term.
Related Guides
How we verified this
This article draws on Ofcom's General Conditions of Entitlement for communications providers, specifically the rules on number portability and switching; Ofcom's published consumer guidance on the text-to-switch system introduced in July 2019; and Ofcom's guidance on early termination charges for mobile contracts.
Disclaimer: Kaeltripton.com is an independent UK editorial publisher. We are not regulated by Ofcom or the FCA and we do not sell or arrange mobile services, insurance, or financial products. This content is for general information only and is not legal, financial, or technical advice. Rules, prices, and operator policies change. Verify the current position with Ofcom, GOV.UK, the ICO, or your provider before acting. ICO registered ZC135439. Last reviewed: 2026-06-05.
Frequently Asked Questions
How do I switch mobile network?
Text PAC to 65075 if you want to take your number with you, or STAC to 65075 if you are happy to leave without your number. Your current operator must send you the code by text within one minute at no charge. Give the PAC to your new operator - online, by phone, or in store - and the switch completes within one working day. No courtesy call to your existing provider is required; the PAC or STAC system handles the switch automatically.
Can I keep my number when switching networks?
Yes. Number portability is a right under Ofcom's General Conditions. Your mobile number is not owned by your operator and you are entitled to take it to any UK network. Text PAC to 65075 from the number you want to port. The PAC is valid for 30 days. Provide it to your new operator and the porting process completes within one working day, with only a brief interruption to service during the actual transfer.
How long does mobile switching take?
Obtaining a PAC or STAC takes under one minute by text under Ofcom's rules. Once you provide the PAC to your new operator, number porting completes within one working day. The actual service interruption during the port is typically only a few hours, usually overnight. The entire process from first text to active new SIM can therefore be completed within two working days in most cases, faster if you are not porting a number and simply taking out a new contract.
What should I check before switching mobile network?
Check whether you are within your minimum contract term and, if so, what your approximate early termination fee would be. Verify coverage for your home, workplace, and regular locations on the new network using Ofcom's checker and the new operator's own tool. Review what your current operator might offer as a retention deal - you will typically receive this automatically when you text for your PAC. Compare the total cost of the new deal over its minimum term against staying on a renegotiated rate.
Is there a cost to switching mobile network?
Requesting a PAC or STAC is free; operators cannot charge for this. If you are outside your minimum contract term, switching is free. If you are within the minimum term, an early termination fee may apply, calculated under Ofcom's rules as no more than the remaining monthly access charges minus a saving reflection. Some operators waive the ETF as part of specific switching or promotional arrangements. Check your current contract's remaining term and ETF clause before initiating the switch.
