It’s quite an easy process ​@Nicola 1 but it means going back to Currys to ask for a replacement SIM (not a new SIM).

Then via the app or online account go to Plan → SIM & phone management → Activate a replacement SIM and follow the prompts (note the first 8 numbers are already filled out)

Sorry to jump in, I have the same problem where I don't have the original SIM, I got a replacement but when I put it in, i just get “no service”. When I try to register, the app prompts me to put in my ID mobile number, but  when I do that the app sends a text to that number, which I cant receive.

Hi ya, I got this sorted yesterday I went to currys and got a new sim card then went to ID mobile site- customer service - chat bot then said lost my sim followed prompt then they put through to a real person and I explained that I haveva sim card from currys and asked them if I could read the number to them under the bar code of new sim for them to transfer my details over this was done I then was told to  wait an hour put the sim card in and refresh phone and it worked didn't take long and was sorted hope this helps 

Hi ​@Nicola 1,

Glad to hear that it is sorted.

If you require further assistance, please let us know.

Kash

Hi Chris

What about this method?

1. Visit this website: https://my.idmobile.co.uk/activate-sim-outside.
2. Tap ‘No, not yet’.
3. Choose your plan type.
4. Enter your iD Mobile number.
5. Select a contact method to receive your security code.
6. Enter your security code.
7. Tap ‘Submit security code’.
8. Enter and confirm your 19-digit SIM card number.
9. Tap ‘Activate your SIM’.

(for number 8 check to see if the first 8 numbers are already filled out)

I have transferred my number from my old provider, the message came through saying it had transferred ok. When i text people it is showing as private number. Also i cant ring people, its showing as the line is busy. When i try to activate my sim its showing as already done. Anyone help?

Hi ​@Bigpreece 

Thank you for the message and sorry that you are having issues with calls.

Can you tell me what is the make and model of the phone you are using?

Michael

Samsung S25FE. I transferred my number from an S23. I had a message to say it was ok

Hi ​@Bigpreece 

We’re currently experiencing a service outage, which may be the reason your calls are affected. However, please try the steps below to see if there’s any improvement, in case the issue is being caused by something else.

Please try the steps below:

You can find your phone number by going to:
Settings > About Phone (or About Device) > Status > My Phone Number
On some devices, this may appear under SIM Status or SIM Card Status.

Update the Number in the Messages App:

Open the Messages app

Tap More (three dots)

Tap Settings

Tap Advanced

Select Phone Number

Edit the number to match the correct number associated with your SIM

Tap OK

If the Issue Continues:

Remove the SIM card

Restart the device

Reinsert the SIM card

Check whether the correct ported number now appears in the Phone settings

If You’re Still Experiencing Issues:

Please try the SIM card in a different device

When sending a text, check whether a temporary number or ported number is displayed