Switch from Three to iD Mobile and keep your number using a PAC code

Last Updated: 29th July 2025

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Are you thinking about leaving Three and switching to iD Mobile? Then you're in the right place! Switching networks and keeping your number in 2025 is simple and easy thanks to Ofcom's policy changes.

We've put together a quick and easy to use switching guide. Our guides allow you to select the network you wish to switch to and from, and you will be given a step by step guide on how to keep your number and move to a new SIM Only Deal.

It is worth noting that if you wish to join iD Mobile and get a new number then you can use a STAC code in order to get a new number and will cancel your existing contract.

Joining iD Mobile and leaving Three

Joining iD Mobile and transferring your number from Three is a simple process and usually takes no longer than 1-2 working days.

The process which will go through in more detail below involves requesting a PAC code from Three and handing it to iD Mobile.

You can either hand the PAC code over to iD Mobile during the ordering process or after you have received your new SIM card or eSIM has been activated.

1. Request a PAC code from Three

You can keep your current phone number, avoiding the hassle of memorising a new one or updating your contacts. You will need a PAC (Porting Authorisation Code) from Three to begin the switch.

Here is how to get it:

• Text: The quickest way is to text "PAC" to 65075 from your Three phone. You will receive your code within 2 minutes. Ofcom, the UK's communications regulator, provides this free service.
• Online: Visit Three's website and request a PAC code through their live chat service.
• Over the phone: Call Three on 333 from your Three SIM or 0333 338 1001 from any other phone.
  • Their customer service line is open;
    • Monday through Friday, 8 am to 8 pm
    • Saturday and Sunday, 9 am to 6 pm.
• In-store: Visit a Three store and request a PAC code from a sales assistant.

Your PAC code is valid for 30 days, so you can request it before or after getting your new SIM card.

If you want a new number and do not wish to keep your current number, you will need to request an STAC code instead of a PAC code. Text "STAC" to 75075 to get your STAC code.

2. Order a SIM only deal from iD Mobile

If you haven't yet ordered your new iD Mobile SIM Only deal, you can use our free comparison engine, which will show you the cheapest iD Mobile deals available on the market.

Compare iD Mobile SIM Only Deals

If you already have your new SIM Card, feel free to skip to step 3 of this article

During the ordering process you may be given the opportunity to share your PAC code from Three to iD Mobile, if you choose this option then the number transfer process will start once your new sim card arrives and you activate it in by putting it in your phone and turning it on, this also means you can skip to step 4 of this article if you wish!

If you are not given the opportunity to hand over your PAC code when ordering then there's no need to panic. Once your new sim card from iD Mobile has arrived, just continue to step 3 of this article.

It is also worth calling out that it doesn't matter if you are able to hand over your PAC code from Three whilst buying your new sim from iD Mobile or not it's just slightly more convenient but the outcome is the same!

3. Give the PAC code to iD Mobile

Once you have your PAC code, here is how to give it to iD Mobile:

• Online: Get your PAC code and the Transaction Number included in your Welcome to iD email. Once you have both, simply click the 'Submit PAC' button on their website to get started.
• Phone: Call 7777 from your iD Mobile phone or 0333 003 7777 from another phone.

iD Mobile will then handle the transfer process. Your number will usually be transferred to iD Mobile within 1-2 working days.

Important Notes:

• Remember to give your PAC code to iD Mobile within 30 days.

4. Wait for your number transfer to iD Mobile to complete

That's it you've done the hard work, now sit back and relax. iD Mobile will notify Three of your intention to leave and take your mobile number to iD Mobile.

The number transfer process will usually take 1 to 2 working days. After this time your Three mobile number will be working on the iD Mobile SIM card.