Call forwarding
Call Forwarding Service UK
Forward calls from a UK landline number to your mobile from £5/month + VAT. ONSIM routes calls at network level — not through a VoIP app — so call quality is as reliable as a normal mobile call, wherever you are.
What is call forwarding?
Call forwarding — sometimes called call divert — routes incoming calls from a business landline number to another number of your choice, usually a mobile. When a customer calls your 01, 02 or 03 number, the call is redirected to your mobile automatically, in real time.
With ONSIM, this happens at network level. There is no app, no broadband dependency and no VoIP drop-out risk. The call arrives on your mobile exactly like any other incoming call.
Why ONSIM is different
Most call forwarding services today use VoIP — your calls travel over the internet via an app. This introduces dependency on Wi-Fi quality, app updates and data availability.
ONSIM routes calls at the mobile network level. That means your calls are delivered the same way as a standard mobile call — reliable signal permitting, with no extra layer of app or internet dependency sitting in between.
How ONSIM call forwarding works
Getting started takes minutes. There is no hardware to set up and no app to install.
1. Get your UK number
Choose a local 01/02 number (Manchester, London, Birmingham and 650+ other area codes) or a national 03 number. Pick the number that fits your business identity.
2. Set your forwarding destination
Enter the UK mobile or landline number you want calls forwarded to. You can change this at any time from your ONSIM dashboard — useful if you are on the move or want to hand off to a colleague.
3. Receive calls — no app needed
Calls to your business number ring on your mobile straight away. Customers see your landline number, not your personal mobile. You answer as you normally would.
Call forwarding vs VoIP
Both approaches let you take business calls on mobile. The key differences come down to reliability, setup and dependency.
| Feature | ONSIM call forwarding | VoIP / app-based |
|---|---|---|
| App required? | No | Usually yes |
| Relies on Wi-Fi or data for calls? | No | Yes |
| Call quality | Standard mobile network | Depends on internet connection |
| Setup complexity | Low — minutes to set up | Medium to high |
| Starting price | From £5/mo + VAT | Typically £10–£30+/user/mo |
Who uses ONSIM call forwarding?
ONSIM is used by sole traders, small businesses and mobile workers who want a professional UK business number without the overhead of a traditional phone system or a VoIP app that depends on internet quality.
Common users include tradespeople, consultants, agencies, landlords, healthcare professionals and anyone who takes business calls on their personal mobile and wants better separation and a more professional number.
Want outbound call forwarding too?
ONSIM Virtual Landline handles inbound calls — calls forwarded to your mobile show your landline number to the customer.
If you also want outbound calls to show your landline number when you dial out, upgrade to ONSIM Landline SIM from £10/mo. Outbound calls are placed natively from your mobile — no app, no VoIP.
Call forwarding FAQs
Common questions about ONSIM call forwarding.
Set up call forwarding from £5/mo
Get a UK landline number that forwards calls to your mobile — no app, no VoIP, no engineer visit. Ready in minutes.