Landline eSIM guide
Landline eSIM on iPhone
Run a UK landline number (01, 02, 03 or 08) on your iPhone as a second line, alongside your personal mobile number. Business calls are labelled as business, missed calls sit in your normal Recents list, and when you call back the person sees your landline number.
From £10/user/month + VAT. No setup fee, monthly rolling, cancel anytime.
Which iPhones work
iPhone 12 or newer, plus iPhone SE (2020 and later). Each of these runs two lines at once (Dual SIM), so your personal number and your ONSIM landline number can both be active. For other models, check the supported devices page before ordering, or use the free eSIM compatibility checker.
Setting up: five minutes
- Order online. Your eSIM QR code arrives by email at checkout.
- On your iPhone open Settings, then Mobile Service (Mobile Data on older iOS), then Add eSIM, then Use QR Code, and scan the code. The iPhone shows "An eSIM from ONSIM is ready to be activated"; tap Continue.
- Give the line a label. iOS offers Business, Personal and others, or you can type your own. This label is what you'll see on every incoming call and in Recents, so choose something obvious like "Business" or "020 Line".
- Under Default Voice Line, choose which number your iPhone uses when you dial a new number manually. Most people keep their personal number as default and switch to the business line when needed (see below).
- Done. Your landline number is live and your personal number carries on exactly as before.
Incoming business calls
When someone calls your landline number, your iPhone rings normally and the incoming call screen shows the line label (for example "Business") under the caller's name or number. You know it's a business call before you answer.
Calls to your personal number show your personal line's label, or no label if you haven't set one.
Missed calls and call history
Missed business calls appear in the iPhone's normal Phone app under Recents, in the same list as your personal calls. Each entry carries the label of the line it came in on, so you can tell a missed business call from a missed personal one at a glance. No separate app, no second call log to check.
Calling back from your landline number
Tap any entry in Recents and your iPhone calls back on the same line the call came in on. A missed call to your 020 number is returned from your 020 number, and the person you're calling sees your landline number, not your personal mobile.
To dial a new number from the business line: enter the number on the keypad, tap the line name shown near the top of the screen (for example "Primary") and choose Use Business Line. Calling someone from Favourites? Tap the Info button, tap the current phone number, then tap your other number.
For contacts you always call from the business line, open the contact, tap last used under their name and, under Always Use, choose Business. iOS then starts every new call and message to that person from your business line.
Outbound calls from the ONSIM line always display your landline number. Calls from your personal line always display your personal number. The two never mix.
Voicemail
Your landline number has its own voicemail mailbox, separate from your personal number's voicemail. You can record your own greeting for it.
By default ONSIM emails each voicemail to you as an audio recording, so you can listen on your iPhone, your laptop or anywhere else without dialling in. You can also dial in from your handset to listen to messages and manage your greeting.
You don't need the Phone app's own voicemail screen for the business line: ONSIM voicemails arrive by email, and dial-in is there when you want it.
WhatsApp Business on your landline number
You can register your ONSIM landline number with WhatsApp Business and run it on the same iPhone as your personal WhatsApp.
- Install WhatsApp Business from the App Store. It runs alongside personal WhatsApp, each on its own number.
- When asked for your number, type your landline number yourself (after +44, without the leading zero). Don't accept a number the app detects from the SIM: that may be the SIM's underlying mobile number rather than your landline.
- Choose verification by phone call, not SMS. UK landline numbers don't reliably receive SMS.
- The verification call rings on your business line. An automated voice reads a six digit code; type it in and you're registered.
ONSIM uses WhatsApp Business too
Our own number, 0333 880 4008, is registered, using the steps above. Message us and see for yourself.
One number can only be on one WhatsApp account at a time. WhatsApp and its business policies are Meta's; ONSIM provides the number and the voice-call verification path. Full guide: WhatsApp Business number.
SMS from the business line (worth knowing)
SMS is sent and received from the SIM's underlying mobile number, not your landline number. UK landline numbers don't reliably support SMS across mobile networks. Voice calls always show the landline number. Marketing or bulk SMS isn't permitted.
Price
£10/user/month + VAT for unlimited UK calls and SMS (fair use 5,000 minutes and 1,000 SMS a month). Optional data: 2GB +£2, 4GB +£4, 10GB +£6, 20GB +£8, 40GB +£10. No setup fee. Monthly rolling, cancel anytime. Port-in of an existing landline number is included.
Frequently asked questions
Running a business landline number alongside your personal number on an iPhone.
Can I run my personal number and the ONSIM landline number on one iPhone?
Yes. iPhone 12 and later models, and the iPhone SE from 2020, run two lines at once. Your personal number stays on its existing SIM or eSIM; the ONSIM landline number is added as a second eSIM. For other models, check the supported devices page before ordering.
How do I know an incoming call is a business call?
The incoming call screen shows the label you gave the ONSIM line, such as "Business", under the caller's number.
Do missed business calls show in my normal call history?
Yes, in Recents in the Phone app, in the same list as your personal calls, each marked with the line label.
If I call back a missed business call, which number does the other person see?
Your landline number. iPhone returns a call on the line it came in on, so a missed call to your 020 number is returned from your 020 number.
Does the business number have its own voicemail?
Yes. Each ONSIM landline number has its own voicemail mailbox with its own greeting, separate from your personal number's voicemail. By default we email each voicemail to you as an audio recording. You can also dial in to listen to messages and manage your greeting.
Can I use the landline number with WhatsApp Business on the same iPhone?
Yes. Install WhatsApp Business from the App Store alongside your personal WhatsApp, enter your ONSIM landline number and choose verification by phone call rather than SMS. The call rings on your business line and reads out the code. See the WhatsApp Business number guide.
How do I know WhatsApp Business registration actually works on an ONSIM number?
ONSIM's own number, 0333 880 4008, is registered on WhatsApp Business. Open wa.me/443338804008 and you'll see the ONSIM business profile; that is the same registration path described on this page.
Is there a setup fee or minimum contract?
No setup fee. Monthly rolling, cancel anytime. £10/user/month + VAT for unlimited UK calls and SMS (fair use 5,000 minutes and 1,000 SMS a month).
Does it need an app or Wi-Fi?
No. Calls run over the mobile network through the iPhone's normal Phone app, with no app to install and no VoIP.
Can I send SMS from the landline number?
SMS is sent and received from the SIM's underlying mobile number, not the landline number. UK landline numbers don't reliably support SMS across mobile networks. Voice calls always show the landline number. Marketing or bulk SMS isn't permitted.