Whether you are out of the office, on another call or simply want every enquiry answered, call forwarding makes sure no call goes unanswered. Also known as call diverting, it is one of the most useful — yet often overlooked — features built into every UK mobile and landline.
In this guide we explain exactly what call forwarding is, walk through the call forwarding codes for EE, O2, Three and Vodafone, show you how to divert calls on iPhone and Android, and explore how businesses use forwarding to deliver a professional customer experience.
What Is Call Forwarding?
Call forwarding (also called call diverting) is a telephony feature that automatically redirects incoming calls from one number to another. Callers dial your original number as usual — they have no idea the call is being sent elsewhere. The redirect happens at the network level, so it works even if your phone is switched off.
UK mobile networks and most business phone lines support call forwarding as a standard feature at no extra monthly cost, although the forwarded leg of the call is charged at your normal call rate.
Types of Call Forwarding
There are four standard types of call forwarding recognised across all UK networks. Understanding the difference lets you set up diversions that match your exact requirements.
Unconditional Call Forwarding
Every incoming call is immediately forwarded to the destination number, regardless of whether your phone is on, off, busy or ringing. This is the most aggressive divert — your phone will never ring. Use it when you want all calls handled by a colleague, receptionist or voicemail service.
Forward When Busy
Calls are only forwarded when your line is already engaged. This is ideal for businesses where a second team member should pick up if the primary contact is on another call.
Forward When No Answer
If you do not answer within a set number of rings (usually 15–30 seconds), the call is redirected. This gives you time to answer but ensures callers are not left waiting.
Forward When Unreachable
Calls are forwarded only when your phone is switched off, in aeroplane mode or out of signal. This is the safety-net divert — it catches calls that would otherwise go nowhere.
Most businesses benefit from combining several types — for example, setting “no answer” and “unreachable” diverts to the office while “busy” diverts go to a colleague’s mobile.
Call Forwarding Codes for UK Networks
Every UK mobile network uses GSM divert codes that you dial from your phone’s keypad. Below are the call forwarding codes UK users need for each major network. To activate a divert, replace number with the full destination number including the leading zero (for example, 07700900123).
EE Call Forwarding Codes
| Divert Type | Activate | Deactivate | Check Status |
|---|---|---|---|
| Unconditional (all calls) | **21*number# | ##21# | *#21# |
| When busy | **67*number# | ##67# | *#67# |
| When no answer | **61*number# | ##61# | *#61# |
| When unreachable | **62*number# | ##62# | *#62# |
| Cancel all diverts | — | ##002# | — |
O2, Three and Vodafone Call Forwarding Codes
The GSM call forwarding codes are standardised across all UK networks, so O2, Three and Vodafone use exactly the same codes as EE shown above. Dial the same activate, deactivate and check-status codes regardless of which network you are on.
| Action | Code |
|---|---|
| Cancel all diverts (all networks) | ##002# |
| Check unconditional status | *#21# |
| Check busy status | *#67# |
| Check no-answer status | *#61# |
| Check unreachable status | *#62# |
How to Set Up Call Forwarding on iPhone
If you prefer not to dial codes manually, iPhones have a built-in call forwarding menu:
- Open Settings.
- Tap Phone.
- Tap Call Forwarding.
- Toggle Call Forwarding to on.
- Tap Forward To and enter the destination number.
This activates unconditional forwarding — every call is diverted immediately. To set conditional diverts (busy, no answer, unreachable), you will need to use the GSM codes listed above, as the iPhone settings menu only supports the unconditional option.
Tip: When call forwarding is active on an iPhone, a small phone icon with an arrow appears in the status bar so you always know diverts are on.
How to Set Up Call Forwarding on Android
Android phones offer more granular control than iPhones through the built-in settings:
- Open the Phone app.
- Tap the three-dot menu and select Settings.
- Tap Supplementary services or Call forwarding (the label varies by manufacturer).
- Select the divert type: Always forward, When busy, When unanswered or When unreachable.
- Enter the destination number and tap Enable or Turn on.
On Samsung Galaxy devices the path is typically Phone > Settings > Supplementary services > Call forwarding. On Google Pixel, look under Calling accounts > your SIM > Call forwarding.
Call Forwarding for Business: Why It Matters
For businesses, call forwarding is far more than a convenience — it is critical to ensuring every customer enquiry is answered. Most callers will not leave a voicemail; they simply call a competitor instead. Here are the most common business use cases.
Out-of-Hours Coverage
Set a “no answer” or “unconditional” divert at the end of the working day so calls route to an out-of-hours answering service or a duty mobile. This means customers calling after 5 pm still get a human response.
Holiday and Sickness Cover
When a team member is off, forward their direct number to a colleague or shared hunt group. The caller never knows the usual contact is unavailable.
Remote and Hybrid Working
Employees working from home can divert their desk phone to a mobile, staying contactable on their usual business number without giving out a personal number.
Sales Teams and Lead Capture
Forward calls from marketing campaign numbers to the relevant sales rep’s mobile so leads are answered instantly. Missed calls cost revenue — call forwarding closes that gap.
If your business regularly relies on call diverting, it may be worth considering a dedicated hosted VoIP phone system that handles forwarding, queuing and routing automatically.
VoIP Call Forwarding: A Smarter Approach
Traditional GSM call forwarding works for simple diversions, but it has limitations — one destination at a time, no scheduling and no intelligent routing. VoIP call forwarding solves these problems. With a cloud-hosted phone system you can:
- Forward to multiple destinations — ring several mobiles simultaneously or in sequence until someone answers.
- Set time-based rules — automatically route calls to the office during working hours and to a mobile or voicemail after 6 pm.
- Use hunt groups — distribute incoming calls across a team so the first available person picks up.
- Route by caller ID — send VIP customers to a dedicated account manager and general enquiries to the main team.
- Manage everything online — change forwarding rules from a web portal or app in seconds, with no divert codes to remember.
For businesses that have outgrown basic mobile diverts, a VoIP system offers significant advantages over a traditional landline, including lower costs, greater flexibility and built-in call forwarding as standard.
Want to see how VoIP forwarding could work for your business? Get a free business mobile quote or call us on 0333 015 2615 to discuss your options.
How to Cancel Call Forwarding
Forgetting to turn off a divert is one of the most common issues businesses face — calls keep going to the wrong place and nobody realises. Here is how to cancel call forwarding on any UK network.
Cancel All Diverts at Once
Dial ##002# and press call. This removes every active divert (unconditional, busy, no answer and unreachable) in one step. It works on EE, O2, Three and Vodafone.
Cancel a Specific Divert
- Cancel unconditional divert: ##21#
- Cancel busy divert: ##67#
- Cancel no-answer divert: ##61#
- Cancel unreachable divert: ##62#
Check Which Diverts Are Active
If you are unsure whether a divert is still running, dial the check-status code for each type (for example, *#21# for unconditional). Your phone will display whether the divert is active and which number it points to.
Cancel via Phone Settings
On iPhone, go to Settings > Phone > Call Forwarding and toggle it off. On Android, open the Phone app, go to Settings > Call forwarding, select the divert type and tap Disable or Turn off.
Call Forwarding Costs: What You Need to Know
Activating call forwarding itself is free on all UK networks. However, the forwarded leg of the call is charged to you at your standard call rate — it uses your inclusive minutes or is billed at your per-minute rate. Forwarding to voicemail is usually free, but forwarding to premium-rate or international numbers can be expensive, so check your tariff first.
For businesses with high call volumes, these forwarding charges can add up. A hosted VoIP system typically includes unlimited internal forwarding and routing at no additional per-call cost, making it far more economical at scale.
Troubleshooting Call Forwarding Problems
If your call forwarding is not working as expected, work through these common fixes:
- Divert not activating — make sure you are entering the full destination number with the leading zero and pressing the call button after the code.
- Calls still ringing your phone — you may have set a conditional divert rather than unconditional. Check with *#21#.
- Divert going to voicemail instead — your network’s default voicemail divert may be overriding your setting. Cancel all diverts with ##002# and set up your preferred divert again.
- Forwarding not working abroad — some networks restrict call forwarding while roaming. Contact your network to check.
Frequently Asked Questions
Is call forwarding free in the UK?
Setting up call forwarding is free on all major UK networks. However, the forwarded call itself uses your inclusive minutes or is charged at your standard per-minute rate. The caller is never charged extra — they pay the same as if they were calling your original number.
What is the difference between call forwarding and call diverting?
Call forwarding and call diverting mean exactly the same thing. “Call forwarding” is more common in technical documentation, while “call diverting” or “divert calls” is used in everyday British English. The codes and functionality are identical.
Can I forward calls to an international number?
Yes, most UK networks allow you to divert calls to an international number. Use the same GSM codes but enter the destination in international format (for example, +3531234567). Be aware that you will be charged international call rates for the forwarded leg.
Will the caller know my calls are being forwarded?
No. Call forwarding is completely transparent to the caller. They dial your number, it connects as normal, and the person at the forwarded destination answers. The caller’s experience is identical to a standard call.
Can I forward calls from a landline to a mobile?
Yes. Most UK landline providers support forwarding to a mobile. On a BT line, dial *21*number# to activate and #21# to cancel — check with your provider for their specific codes. If you are considering moving away from a traditional landline, our guide to VoIP vs landline for business explains the options.
How do I forward calls only during certain hours?
Standard GSM call forwarding does not support time-based rules — you would need to manually activate and deactivate the divert each day. For automatic scheduling, a cloud-hosted VoIP system lets you route calls to different numbers depending on the time of day, day of the week or bank holidays.
Can I forward calls to more than one number?
Not with standard GSM call forwarding — each divert type can only point to one destination at a time. If you need calls to ring multiple phones simultaneously or in sequence, you will need a VoIP system with hunt-group functionality. Get a free business mobile quote to explore multi-destination options.
Does call forwarding work when my phone is off?
Yes. The “when unreachable” divert (**62*number#) activates specifically when your phone is off, in aeroplane mode or has no signal. Unconditional forwarding (**21*number#) also works regardless of your phone’s status because the network redirects the call before it reaches your handset.
Next Steps: Get Better Call Management for Your Business
Call forwarding is a powerful tool that every UK business should be using — but if you find yourself constantly juggling divert codes, it may be time to upgrade to a hosted VoIP system that handles routing automatically with time-based rules, hunt groups and call queuing.
Connection Technologies helps UK businesses of all sizes set up smarter call management — from straightforward mobile diverts to full cloud phone systems.
Get a free business mobile quote or call our team on 0333 015 2615 to discuss your call forwarding and business phone needs.