How do you switch UK mobile provider and keep your number in 2026?

What do you need before switching UK mobile provider?

Active SIM in hand · ID for postpaid · payment method · final-bill awareness

You need four things: a live UK SIM that can still send SMS, a photo ID if you're moving onto a credit-checked postpaid plan, a payment method for the new provider, and 30 seconds to text PAC to 65075. UK pay-as-you-go SIMs are anonymous — Ofcom does not require SIM registration — so prepaid switches need no ID at all.

How does UK PAC porting actually work?

Ofcom mandate · donor + recipient handshake · routing database swap

PAC porting is a regulated handover between two operators — your donor (old) and your recipient (new). Ofcom's General Conditions C7 require every UK mobile operator to offer free, 24/7 Text-to-Switch via the universal short codes 65075 (PAC) and 75075 (STAC). The 9-character PAC tells the recipient's port team which donor to claim the number from, and the routing change is pushed to the UK national porting database overnight.

1. You text PAC to 65075. Your donor must reply within one minute with the code, your remaining contract end date, any early termination fee, and your final bill estimate. (Ofcom SLA — written into General Conditions C7.6)
2. You hand the PAC to the recipient. Done at checkout on the new provider's website, in their app, or by phone. The recipient submits a port request to the donor through the Mobile Number Portability Operator (MNPO) hub.
3. The donor validates the PAC. Code must match, number must belong to you, account must be in good standing. Mismatch → donor rejects, you go back to step 1.
4. The MNPO hub schedules the cut-over. Routing data is updated overnight. Inbound calls and SMS are redirected from the donor network to the recipient network at the cut-over instant.
5. The recipient activates the line by 17:00 next working day. Your old SIM stops registering on the donor network. Your new SIM (physical or eSIM) takes over the number.
6. Your old contract auto-cancels. No phone call to your old provider needed. The final bill arrives within 30 days.

Three pieces of infrastructure make this work: Ofcom's General Conditions C7 (the legal mandate, in force since 1 July 2019), the universal short codes (65075 and 75075, free to text from any UK SIM), and the MNPO porting hub jointly operated by EE, O2, Vodafone and Three. No operator can refuse a valid PAC, charge for it, or take longer than one working day — non-compliance triggers Ofcom enforcement action under section 96 of the Communications Act 2003.

How do you switch UK SIM in 5 steps?

Pick · PAC · order · wait · confirm

The full switch is five discrete steps spanning about 24 hours end-to-end — perhaps 15 minutes of active work. Pick your new plan, text PAC to 65075 from the old SIM, give the code to the new provider at checkout, wait one working day, then test and dispose of the old SIM. There is no service gap — your old SIM keeps working right up to the cut-over moment.

1. 1

   Pick your new SIM

   Compare plans in the UK comparison hub by price, data, EU roaming, 5G, and host network. Switching does not change your phone number — only the plan and provider. If you're not sure which host network covers your address, check Ofcom's Mobile Coverage Checker at checker.ofcom.org.uk before you commit.

   timer 5–10 min
2. 2

   Text PAC to 65075

   From your existing UK SIM, send the word PAC (capitalisation does not matter) to 65075. Within one minute your donor replies with: your 9-character PAC code, your final bill estimate, any early termination fee, and the code's 30-day expiry date. Free of charge, no human in the loop.

   sms 1 minute
3. 3

   Order with the new provider & hand over the PAC

   Sign up online, in-app, or in-store. At checkout, paste the PAC code in the "Keep your existing number" field and confirm the number you want to port. The new provider sends a confirmation SMS to your old SIM listing the scheduled cut-over date.

   shopping_cart 5 min
4. 4

   Wait one working day

   The recipient activates the line by 17:00 the next working day. Your old SIM keeps working until the cut-over instant. You may see "No service" for a few minutes — pop in the new SIM (or activate the eSIM QR) and the number reappears on the new network.

   schedule 1 working day
5. 5

   Confirm, re-register voicemail, dispose of old SIM

   Make a 1-minute test call from the new SIM, send a test SMS, then re-register voicemail (dial 121 on most UK networks and re-set your PIN). Toggle iMessage and RCS off-and-on to force re-registration on the new network. Cut up the old SIM card. Final bill arrives within 30 days.

   check_circle 5 min

When should you switch — timing tricks for UK porting?

Billing-date alignment · weekend submission · bank-holiday trap

Ofcom's one-working-day clock starts when the recipient files the port request — not when you submit the order. Order Monday to Thursday before 17:00 and you'll cut over the next afternoon. Order on a Friday, Saturday or Sunday and the port slips to Monday or Tuesday. To avoid being billed twice in the same month, time the switch within three days of your billing anniversary on the donor account.

Source: Ofcom General Conditions C7 (Text-to-Switch) · enforced since 1 July 2019, verified May 2026

• Align with your billing anniversary. Most UK postpaid plans bill for a full month even if you cut over mid-month. If your donor bills you on the 5th, ideally trigger the switch on the 3rd or 4th so you don't pay for 27 unused days.
• Avoid Friday afternoon orders. Submit before Thursday 17:00 if you want a same-week cut-over. A Friday 18:00 order means three full days on the donor before the port lands on Monday.
• Bank-holiday trap. The Monday after Easter, May Day, Spring and August bank holidays count as non-working days. Christmas Eve through 2 January is effectively dead time for porting on most networks — many port teams operate skeleton crews.
• Keep at least 2 GB of data on the old SIM. 4G/5G hotspot is the easiest fallback if the cut-over runs a few hours late and you depend on the line for 2FA codes.

What if PAC porting goes wrong?

Mismatched details · missed cut-over · iMessage stuck · lost voicemail

Most port failures trace back to four root causes: name or address mismatch between donor and recipient accounts, an expired PAC (older than 30 days), unpaid balance on the donor account, or iMessage / RCS still bound to the old network. Ofcom requires the recipient to chase the donor automatically — you don't need to call. If the port misses the 17:00 deadline, you're entitled to automatic compensation.

Source: Ofcom Automatic Compensation Scheme rates · General Conditions C7 enforcement notices, verified May 2026

Should you keep your number or get a new one?

PAC for continuity · STAC for a fresh start

Keep your number (use a PAC) if it's tied to banking 2FA, WhatsApp, work contacts, or government services. Get a new number (use a STAC) if you want to escape spam, harassment, or a phone-scam list, or if the number has been published somewhere you regret. Both routes are free, both take one working day, both texted from the same SIM — PAC to 65075, STAC to 75075.

STAC is also the right call if you're a long-term traveller who doesn't want the UK number any more — for example, if you've emigrated and want to close the line cleanly without porting it to a foreign operator (international PAC porting between countries is not supported). One nuance: a STAC closes the line but does not waive any outstanding contract balance, so you'll still owe any early termination fee.

How do you switch if you're mid-contract?

Eligibility · early termination fee · CPI rise exit window

You can still switch mid-contract — Ofcom does not let an operator block a port — but you'll pay an early termination fee (ETF) covering the remaining monthly line rental, often discounted by 4–5% for early settlement. Two exceptions where the ETF is waived: a mid-contract price rise above the rate disclosed at sign-up triggers a 30-day fee-free exit window, and any material change to service terms also gives you a right to cancel under General Conditions C1.

• Check your remaining months. Text INFO to 85075 from your current SIM. The donor replies with months left, monthly cost, ETF total, and any handset balance.
• Subtract any included handset value. If the contract bundled a phone, the handset balance is usually due in full alongside the airtime ETF. Splitting the handset and airtime — a "Flex", "Split contract" or "Airtime Plan" — protects against this.
• Use the price-rise window. EE, Vodafone and O2 have shifted to pounds-and-pence yearly rises (typically £1.50–£2.50/month). The Ofcom April 2025 ruling requires the exact rise figure to be disclosed at sign-up — any deviation gives you a fee-free exit window of 30 days.
• Don't cancel the old contract first. The PAC process auto-terminates the donor account at cut-over. Calling to cancel early can cost you the line before the new one activates.
• Compare ETF vs new-plan savings. If you have 3 months left at £28/month, ETF is roughly £80. Switching to a £10/month MVNO saves £18/month thereafter. Breakeven is about 4.5 months — often worth it for a 24-month new plan.