A verification code sent to your spare number arrives as an ordinary text message on the spare line, in the same Messages app you already use. Because the spare line is a real UK mobile number on a real network, services treat it like any other mobile: the code is delivered, and nothing about your main number is involved.
The one thing to get right is knowing which line you gave to which service, so you look in the right conversation.
Why a real mobile number matters
Most sign-up flows check the number you enter before they send anything. Numbers that belong to internet-calling and virtual number services sit in publicly known ranges, and a great many services simply refuse them, either at the point of entry or by silently never delivering the code.
- Virtual and VoIP numbers are commonly rejected at sign-up, or accepted then blocked later.
- Shared or disposable numbers may already have been used to register the same service by someone else.
- A real mobile number on a mobile network is the format these checks are built around.
- Landline and non-mobile numbers are refused by most services that require SMS.
Our numbers are ordinary UK mobile numbers starting 07. They are not disposable, not shared with anyone else, and not routed over the internet. For the fuller comparison, see eSIM vs virtual number apps.
Receiving a code, step by step
- 1
Find your spare number
Check it in your phone SIM settings, or in your account area. Copy it out in full so you enter it correctly, in the 07 format the service asks for.
- 2
Make sure the spare line is switched on
A line that has been toggled off, or a phone in flight mode, will not receive anything. Check the spare line shows signal before you request a code.
- 3
Enter the spare number at sign-up
Type the spare number into the service, not your everyday one. Double-check the digits: a typo means the code goes to a stranger, and you will be left waiting.
- 4
Wait for the text on the spare line
The message usually arrives within seconds. Open Messages and look for the conversation received on the Spare line rather than your main one. If your phone colour-codes lines, the label tells you which is which.
- 5
Enter the code promptly
One-time codes expire, often within a few minutes. If it has been sitting there a while, request a fresh one rather than trying an old code.
- 6
If nothing arrives, request one resend, then wait
Repeatedly hitting resend can get you rate-limited by the service and slow things down further. Send one more request, give it a couple of minutes, and if it is still quiet try the voice-call option many services offer.
Which line gets what
| What happens | Which line | Why |
|---|---|---|
| Code for an account registered to the spare number | Spare | Codes follow the number you gave the service |
| Code for your bank, registered years ago | Main | Nothing moves unless you change it with them |
| Someone calls your spare number | Spare | It rings on your phone, shown as the spare line |
| You call someone | Main, by default | Your default line is unchanged unless you pick the spare |
If you have not yet chosen which line is default, how to set up your spare eSIM walks through it. Keeping your main line as the default means outgoing calls and data behave exactly as they did before.
Practical tips
- Keep the line active. If you switch the spare line off to save battery, you will miss codes. Turn it back on before requesting one.
- Check the right conversation. In Messages, the thread is tagged with the line it arrived on. Filter or scroll to the spare line rather than assuming nothing came.
- Write the number down somewhere safe. People forget a number they never dial themselves.
- Expect a re-check. Some services re-verify months later, so treat the spare number as one you intend to keep, not a throwaway.
- Do not share codes. Nobody legitimate will ever ask you to forward one, and we will never ask for it.
Register the account to the number you intend to keep. Future you will be asked to prove it again.
Using the spare number for messaging? Second number for WhatsApp covers the registration side, or you can go straight to the plans: see the WhatsApp plan and see the Telegram plan. We are not affiliated with, endorsed by or sponsored by WhatsApp, Meta or Telegram.
Common questions
Will verification codes go to my main number by mistake?
No. Codes are sent to whichever number you typed into the service. If you registered with the spare number, only the spare line receives them.
Can I receive codes from services outside the UK?
Yes, international SMS to a UK mobile number is normal. Delivery still depends on the sending service, and a small number of senders restrict which countries they will text.
What if a service says my number is not valid?
Check the format first: enter it as a UK mobile, and use the international form with the leading zero dropped if the field asks for a country code. If it still refuses, that service is likely blocking something other than the number type.
Do I need to keep the spare line active after verifying?
Yes, and it matters more than people expect. Services often re-verify, and account recovery usually depends on receiving a code, so a lapsed line can lock you out.
Get a spare number
A real UK line that lives on your phone as an eSIM, beside the SIM you already have. Installed in minutes.