Virtual phone numbers
Virtual Phone Number UK
A virtual phone number is a real UK number that is not tied to a desk phone or a fixed line - calls route to wherever you are, usually your mobile. Most providers deliver virtual numbers through a VoIP app. ONSIM delivers them over the mobile network from £5/month + VAT, so calls arrive like normal mobile calls: no app, no Wi-Fi dependency, no dropouts.
Types of virtual phone number
Virtual number is an umbrella term. The number type you pick changes how your business comes across, not how the routing works.
Local numbers (01 and 02)
A geographic number that anchors you to a town or city - London 020, Manchester 0161, Birmingham 0121 and 650+ other UK dial codes. The best choice when customers prefer to buy local.
National numbers (03)
An 0330 or 0300 number gives you a UK-wide presence without tying you to one area. 03 numbers cost callers the same as calling an 01 or 02 number and are included in most call allowances.
Freephone numbers (08)
0800 and 0808 numbers are free for callers to dial, which can lift inbound enquiry volume for sales lines. Freephone numbers are available on the ONSIM Landline SIM plan.
Mobile numbers (07)
A separate 07 identity for your business, without carrying a second handset. An ONSIM SIM can hold multiple landline and mobile numbers at once, and you choose which number to show on each outbound call.
How ONSIM delivers virtual numbers differently
Most virtual number services are VoIP: your calls are converted to data and travel over the internet through an app. That means app installs, logins, notification permissions and call quality that rises and falls with your Wi-Fi.
ONSIM works at network level instead. In divert mode, calls to your virtual number are forwarded to your existing mobile as standard phone calls. On a supported device, the same number can be delivered natively over a SIM/eSIM, so you can also make outbound calls showing your business number.
Why that matters
- Nothing to install: no softphone, no app updates, no separate dialler to remember.
- No internet dependency: calls do not drop because a coffee shop Wi-Fi hiccupped.
- Native call quality: the call is a normal mobile call end to end.
- A real upgrade path: start with a £5/mo divert, move to a SIM-native number later without changing provider or number.
App-based virtual numbers vs ONSIM network-level
| Feature | ONSIM network-level | Typical app-based provider |
|---|---|---|
| How calls arrive | Normal mobile call, native dialler | VoIP call inside an app |
| App required | No | Yes |
| Relies on Wi-Fi or data | No | Yes |
| SIM-native option | Yes - number on a SIM/eSIM | No |
| Outbound calls showing the number | Yes, on Landline SIM | Via the app only |
| Starting price | £5/mo + VAT | Typically £10 to £30+/user/mo |
Virtual phone number pricing
Inbound calls on your mobile
Virtual number with divert
£5/mo + VAT
- UK 01, 02 or 03 number of your choice
- Calls forwarded to your existing mobile
- Up to 2,500 forwarding minutes per month, fair use
- Live in minutes, cancel any time
Inbound and outbound identity
SIM-native virtual number
£10/user/mo + VAT
- Your number on a SIM/eSIM - calls ring natively
- Outbound calls show your virtual number
- Unlimited UK calls and SMS, fair use
- Hunt groups, voicemail, deskphone pairing available
Want a landline-style number specifically? Our Virtual Landline page covers the 01/02/03 product in depth, and you can keep an existing landline number by porting it in.
Virtual phone number FAQs
Common questions about getting a UK virtual number with ONSIM.
Get your UK virtual phone number today
Pick a number, point it at your mobile and start taking business calls in minutes - over the mobile network, not an app.