How to Divert Calls from Landline to Mobile UK

Updated March 2026

Whether you’re working from home, heading out for the day or moving offices, diverting your landline to a mobile means you never miss an important call. The process takes under a minute on most UK providers — but the ongoing costs and limitations are worth understanding before you set it up.

This guide covers the exact divert codes for every major UK provider, what it costs, and why thousands of businesses are switching to VoIP instead of paying for call diversion.

How to Divert a BT Landline to Mobile

BT is the UK’s largest landline provider, and their call diversion service uses star codes dialled directly from your handset. No engineer visit or account changes required.

Step 1: Choose Your Diversion Type

BT offers three diversion modes, each suited to different situations:

Step 2: Activate the Diversion

1. Pick up your BT landline handset and wait for the dial tone
2. Dial the appropriate star code — for example, *21*07700900123# to divert all calls to 07700 900 123
3. Listen for the confirmation tone (a short burst of dial tone followed by a continuous tone)
4. Replace the handset — the diversion is now active

The diversion activates immediately. Test it by calling your landline from another phone to confirm calls are reaching your mobile correctly.

Step 3: Cancel When No Longer Needed

To stop the diversion, pick up the handset and dial the corresponding cancel code (e.g. #21# for all-call diversion). You’ll hear a confirmation tone and your landline will ring normally again. If you’ve set up multiple diversion types, you’ll need to cancel each one separately.

How to Divert Sky or TalkTalk Landline to Mobile

Sky and TalkTalk landlines run on the Openreach network — the same infrastructure as BT — so the diversion codes are identical:

• Divert all calls: *21*[mobile number]#
• Divert on busy: *67*[mobile number]#
• Divert on no answer: *61*[mobile number]#
• Cancel all diversions: #21#, #67# or #61# respectively

The activation process is identical to BT: pick up the handset, dial the code, wait for the confirmation tone. If the star codes don’t work on your line, your provider may have migrated you to a digital voice service. In that case, you’ll need to set up diversion through their online portal or app instead.

Virgin Media Landlines

Virgin Media operates its own cable network, so the codes differ slightly:

• Divert all calls: *21*[mobile number]#
• Divert on busy: *67*[mobile number]#
• Divert on no answer: *61*[mobile number]*[seconds]# (where seconds is 10, 15, 20, 25 or 30)
• Cancel: ##21#, ##67# or ##61#

Note the double hash (##) for cancellation on Virgin Media lines — using a single hash won’t work.

How to Divert VoIP Calls to Mobile

If your business already uses a VoIP phone system, call diversion is built into the platform and far more flexible than star codes. There are no per-minute charges and you can manage everything from a web dashboard.

Using the Admin Portal

1. Log in to your VoIP provider’s admin dashboard
2. Navigate to Call Routing or Call Forwarding settings
3. Select the extension or number you want to divert
4. Enter the mobile number as the forwarding destination
5. Choose conditions: always, on busy, on no answer, or outside business hours
6. Save the changes — they take effect immediately

Using a Softphone App

Most VoIP providers offer a mobile app that turns your smartphone into an extension of your office phone system. Instead of diverting calls, you simply answer them on the app — using your business number, not your personal mobile number. This is a significant advantage over traditional call diversion because your callers always see a professional number and you keep personal and business calls separate.

With VoIP, you can also set up sophisticated routing rules that aren’t possible with star codes:

• Time-based routing: Calls go to your desk phone during office hours, your mobile after 6pm
• Sequential ringing: Ring your desk phone first, then your mobile after 4 rings
• Simultaneous ringing: Ring both your desk phone and mobile at the same time
• Failover routing: If your internet goes down, calls automatically route to a mobile backup

For a detailed walkthrough of every forwarding option, see our complete guide to call forwarding.

Costs of Diverting Landline Calls to Mobile

This is where traditional call diversion gets expensive. When you divert a landline call to a mobile, you pay for the diverted leg of the call at your provider’s standard landline-to-mobile rate. The caller pays nothing extra — the cost falls entirely on you.

For businesses that divert calls regularly, the charges add up alarmingly fast. A company taking 10 diverted calls a day on BT could spend over £150 per month on diversion charges alone — more than the cost of a full VoIP system. For a deeper comparison, read our VoIP vs landline guide.

Permanent vs Temporary Diversion

Temporary Diversion

Temporary diversion suits short-term needs — a meeting, a day out of the office, or a week’s holiday. Activate the star code before you leave and cancel when you return. The main risk is forgetting to cancel it: you’ll rack up diversion charges without realising, and callers may wonder why your landline never rings.

Best for: Occasional out-of-office days, short holidays, one-off events where you need mobile reachability.

Permanent Diversion

If you’ve moved to remote or hybrid working and rarely use your landline handset, permanent diversion keeps your number active while routing every call to your mobile. However, this approach has significant drawbacks for long-term use:

• Expensive: You pay landline-to-mobile rates on every single call (see cost table above)
• Lost features: You lose voicemail, caller ID display and call waiting on the landline
• No flexibility: All calls go to one mobile number — no team routing, no time-based rules
• PSTN switch-off: BT is retiring the traditional phone network by January 2027, so landline diversion has a limited lifespan anyway

A better option for permanent diversion: Port your landline number to a VoIP provider. You keep the exact same number, but calls arrive over the internet — on your mobile app, desk phone or laptop. No diversion charges, no star codes, and you gain features instead of losing them.

Better Alternative: Switch to VoIP

If you find yourself regularly diverting landline calls to a mobile, it’s worth asking whether a VoIP system would serve you better. Here’s a direct comparison:

With a hosted VoIP system, calls follow you automatically — on your desk phone, laptop or mobile app. There are no divert codes to remember, no per-minute charges for forwarded calls, and your callers always see your professional business number. For businesses still relying on traditional landlines, the UK call forwarding landscape is shifting fast as the PSTN switch-off approaches.

Troubleshooting Common Diversion Issues

Star codes not working

If dialling the star code doesn’t produce a confirmation tone, your line has likely been migrated to a digital voice service (increasingly common as providers prepare for the 2027 PSTN switch-off). Contact your provider and ask them to enable call diversion through their online account portal or app.

Calls going to voicemail instead of your mobile

Check that your mobile isn’t set to Do Not Disturb and that you have adequate signal. Also verify the mobile number in the diversion code is correct — a single wrong digit will send calls to a stranger’s phone or to a dead line.

Diversion charges higher than expected

Diverted calls are charged per minute at your landline-to-mobile rate, and they’re almost never included in call packages. If you’re seeing unexpectedly high bills, check how many minutes of diverted calls you’re actually using — it adds up faster than most people expect.

Frequently Asked Questions

Can I divert a landline to a mobile for free?

Setting up the diversion itself is free on all UK providers. However, each diverted call is charged at your provider’s landline-to-mobile rate (typically 10–15p per minute). The only way to forward calls to a mobile for free is through a VoIP system, where forwarding is included in your monthly plan.

Does the caller know their call has been diverted?

No. The caller dials your landline number and hears normal ringing. They won’t know the call has been forwarded to a mobile unless you tell them.

Can I divert my landline to an international mobile number?

Yes, but you’ll be charged international call rates for every diverted call, which can be extremely expensive. If you need to take UK business calls while abroad, a VoIP softphone app is a far cheaper solution — calls route over Wi-Fi or mobile data at no extra charge.

What happens to my landline when I set up diversion?

Your landline number stays active and callers dial it as normal. With “divert all calls” active, your physical handset won’t ring — calls go straight to your mobile. With “divert on no answer” or “divert on busy”, your handset still rings first.

Will landline diversion still work after the 2027 PSTN switch-off?

BT is switching off the traditional phone network by January 2027. After that, all calls will run over digital lines. Call diversion should still be available on the new digital services, but the method of setting it up may change — star codes may be replaced by online portals. If you’re planning ahead, switching to VoIP now avoids the disruption entirely.

Related reading:

• Call Forwarding UK Guide
• Call Forwarding: A Complete Guide
• VoIP vs Landline for Business UK