What Is Call Forwarding?

Call forwarding — also known as call diverting — is a standard mobile feature that redirects your incoming calls to another phone number. Whether you are heading into a meeting, switching devices or simply want calls routed to a colleague, call forwarding ensures you never miss an important call.

How Does Call Forwarding Work?

When call forwarding is active, your mobile network intercepts incoming calls before they reach your handset and redirects them to the number you have specified. The caller usually has no idea the call has been diverted — it simply rings at the new destination instead.

All UK networks support call forwarding as a standard GSM feature. You can activate it through your phone settings, your network's app, or by dialling short star codes directly from your keypad.

Types of Call Forwarding

There are four types of call forwarding available on every UK mobile network:

• Unconditional (all calls) — Every incoming call is forwarded immediately, regardless of whether your phone is on or off. Your handset will not ring at all.
• When busy — Calls are forwarded only when you are already on another call and cannot answer.
• No answer — Calls are forwarded after a set number of rings (usually 15–30 seconds) if you do not pick up.
• When unreachable — Calls are forwarded when your phone is switched off, in aeroplane mode, or has no signal.

You can combine conditional types — for example, forwarding to voicemail when unreachable but to a colleague when busy — giving you flexible control over how your calls are handled.

Star Codes Overview

The quickest way to set up call forwarding on any UK network is with universal GSM star codes. These short codes are dialled from your phone's keypad and work on EE, Vodafone, O2, Three, giffgaff, and every other UK MVNO.

For example, to forward all calls you would dial **21* followed by the destination number and #. To cancel, dial ##21#. We cover every code in detail in our Call Divert Codes guide.

Is Call Forwarding Free?

Activating or deactivating call forwarding is free on all UK networks. However, forwarded calls may be charged at your standard outgoing call rate because the network treats the redirected leg as a new outgoing call from your number. If you have inclusive minutes, forwarded calls will typically come out of that allowance.

When Should You Use Call Forwarding?

Call forwarding is ideal for anyone who needs to stay reachable across multiple numbers or devices. Common scenarios include forwarding a work mobile to a desk phone, routing calls to a teammate while on annual leave, or sending missed calls to a virtual receptionist.

Need advanced call routing for your business? Connection Technologies can set up intelligent call forwarding, hunt groups and VoIP integration for your team. Get in touch to find out more.