STAC Code: How to Leave Your Network Without Your Number
A STAC code (Service Termination Authorisation Code) is the free code that lets you leave your mobile network without keeping your number. Text STAC to 75075 from the phone you are leaving, and the code arrives within a minute. Give it to your new network when you sign up, and they close your old account within one working day. The code is valid for 30 days. If you want to keep your number, you need a PAC code instead, from 65075.
That is the whole process. The rest of this guide covers what the STAC does to your contract and your old number, what it costs if you are still in your minimum term, and the mistakes that bring people to the networks’ forums every week.
In short: send the INFO text to see any leaving charges → text STAC → give the code to your new network → your old number is switched off for good. Want the number? Send PAC, not STAC.
What is a STAC code, and how is it different from a PAC?
Both codes come from the same Ofcom switching system, introduced in July 2019, and both end your old service. The difference is what happens to the number. A PAC moves it to your new network. A STAC releases it: the number is disconnected and, after a holding period, goes back into the pool to be reused.
| You want to | Code | Text | Your old number |
|---|---|---|---|
| Switch network and keep your number | PAC | PAC to 65075 | Moves with you |
| Switch network and start with a new number | STAC | STAC to 75075 | Switched off for good |
| Check what leaving will cost | INFO | INFO to 85075 | Nothing changes |
The INFO text is the one most people skip. It shows any early termination charge, or your prepaid balance, without starting anything. Send it first.
How to get your STAC code on each network
The text route works on every UK network because Ofcom requires it. Send STAC to 75075 from the number you are leaving, and the reply comes within 60 seconds. It is free. The networks also offer their own routes, which you need if your account has more than one number: the text route only handles the number it is sent from.
| Network | Other ways to get a STAC | Worth knowing |
|---|---|---|
| EE | An EE STAC can also come from your online account (one-time PIN) or by phone | Accounts with several numbers must use the account or phone route. Final bill within 14 days of the switch. |
| O2 | Ask O2 directly | Moving to a new O2 plan? You can just take a new O2 number; no STAC needed. |
| Vodafone | My Vodafone, or by phone | More than one number: check leaving fees in My Vodafone rather than by INFO text. |
| Three | My3 → Manage your plan → Leave Three, or call 0333 338 1082 | Three asks for your date of birth in the text: send STAC plus DDMMYY, for example STAC060385. |
| giffgaff | Call 43431, or your Profile and settings page | You need to be in the UK to request it. |
| Tesco Mobile | My Account → Manage my details → Request your PAC code | Only the account holder can ask. Use the account route for several numbers. |
Smaller networks such as iD Mobile, Lebara, SMARTY and VOXI follow the same text route; the smaller-network PAC guide lists their phone and app options. If you need the iD Mobile or giffgaff specifics, those guides cover both codes.
How to use a STAC code
- Sign up with the new network first. Get the new SIM or eSIM working on its temporary number.
- Give them the STAC. Most networks have a box for it in the app or on the website; O2, for example, takes it in My O2.
- Wait a working day. The new network sends the code to your old one, which closes the account. Your old SIM stops working at that point.
- Keep paying by direct debit until the final bill clears. Cancelling it early leaves a debt on your old account and does not end the contract.
You do not need to phone your old network to cancel, and you do not give notice. Ofcom banned providers from charging for a notice period that runs past the switch date, so the account ends on the day the switch completes. If you still have the old SIM in a drawer afterwards, it is dead: the STAC closes the number, not just the plan.
What a STAC code costs
The code itself is free. What you may owe is an early termination charge if you are still inside your minimum term. The STAC does not cancel that. Three puts it plainly: the fee is “equivalent to the monthly charges left during the minimum term of your agreement”. EE’s version, which it calls a Remaining Contract Charge, is the outstanding monthly charges minus recurring discounts, less VAT and a 4% early-payment deduction, with VAT added back at the end. In the last month of the contract, EE charges a month’s line rental instead.
Two things the STAC does not touch:
- A separate phone loan. Device plans such as Three Your Way and O2 Refresh carry on. You keep paying for the handset, or settle the balance.
- Linked plans. Three ends a paired smartwatch plan with the airtime and adds its early termination fee to the final bill.
So send INFO to 85075 before you decide. If the fee is large, the usual alternative is to request the STAC in the last month of the contract, when it costs nothing to leave.
Pay as you go: what happens to your credit
Leaving with a STAC or PAC is the one case where pay as you go credit can usually be refunded, because the network can see you switched rather than let the SIM lapse. The rules differ:
- Three: sends your balance with the code; ask for the refund within 90 days of the account closing.
- Tesco Mobile: request a refund of pre-paid credit through web chat after switching.
- EE: tells you to use the credit before you switch, because it is lost once the switch completes.
- giffgaff: does not refund remaining credit or unused plan days after a port-out.
Cheapest answer on any network: spend the balance first.
Mistakes people make with STAC codes
Sending STAC when you meant PAC
This is the costly one. People read “STAC” as a typo for “stack”, or assume it is the newer version of the PAC, and hand it to the new network. Once the switch goes through, the number is disconnected. EE’s community team has told customers the same thing: after a STAC has closed the account, the number cannot be recovered. If you have requested a STAC by mistake but not yet used it, just let it expire, or ask the network to cancel it. On Three, a live PAC has to be cancelled before a STAC can be issued.
Texting from an account with several numbers
The 75075 text can fail silently on family and business accounts. If nothing arrives after a couple of minutes, check you sent it from the number you are closing, then use your online account or call.
Getting a STAC when you are not switching
A STAC only does something when a new network submits it. If you are simply cancelling, with no new provider, the code sits unused and your contract carries on. Three warns that the account “will stay open, and you’ll continue to be charged”. To cancel outright, contact your network and give notice, usually a month.
Letting a number go that was worth something
Numbers with repeated or patterned digits sell. If yours is a premium mobile number you paid for, or one you have had for twenty years, a PAC to a cheap SIM keeps it alive for a few pounds a month. The STAC is permanent.
Common questions
Does a STAC code cancel my contract?
Yes, once your new network uses it. The account closes on the switch date and billing stops from then. Any early termination charge and the final month’s usage arrive on the final bill.
Can I change my mind after requesting a STAC?
Yes, as long as you have not given it to a new network. Do nothing and it expires after a month; your service continues as normal. If you have already handed it over, call your old network straight away and ask them to stop it. After the switch completes, it is too late.
Can I get my old number back?
Not in practice. The networks treat a STAC disconnection as final. Which? found that giffgaff holds released numbers for a year and Three for at least 18 months before reuse, but holding is not the same as reactivating, and customer services will not restore it.
How long does a STAC switch take?
Your old number and service are normally disconnected within a working day of the new network submitting the code. If it takes longer, the new network is responsible for chasing it.
Is “stack code” the same thing?
Yes. It is spelt STAC, for Service Termination Authorisation Code, but plenty of people hear it as “stack”. The text to send is STAC, with no K.
The short version
Check the leaving cost with INFO to 85075. If you are happy to lose the number, text STAC to 75075, give the code to your new network, and the old account closes within a working day. If there is any chance you want the number later, send PAC instead.
Sources
- Ofcom — Switching mobile phone provider, on the switching texts, the one-minute reply, 30-day validity and the notice period ban.
- EE — What you need to know if you want to leave EE, on request routes, the Remaining Contract Charge, multi-number accounts and credit.
- O2 — How to disconnect your old number, on the 60-second reply and the working-day switch.
- Vodafone — What are PAC, STAC and INFO codes, on the INFO text and multi-number accounts.
- Three — Leave without your number, on the date-of-birth text, My3, fees, linked plans and unused codes.
- Three — Leave Pay As You Go, on credit refunds within 90 days.
- giffgaff — Getting a PAC or STAC to leave giffgaff, on 43431, the UK requirement and credit.
- Tesco Mobile — Switching to another network, on the account-holder rule, refunds and final bills.
- Which? — Recycled phone numbers, on how long released numbers are held (October 2024).
Last reviewed 4 November 2026. Network processes and fees change; this guide is re-checked when they do.
