How to Forward Calls on Any UK Phone (2026 Guide)

Call forwarding sends incoming calls from one phone to another number automatically. Dial a short code or flip a setting, and a call to your mobile or landline rings somewhere else instead — your personal mobile, a colleague, your office line, or anywhere you choose. It is one of the oldest and most useful tricks on any phone, and it takes about thirty seconds to set up.

This guide covers every method that works in the UK in 2026: the quick GSM codes, the menu options on iPhone and Android, how to set a divert on a BT landline, and conditional forwarding for when you are busy or do not answer. It also covers the one thing forwarding cannot fix — and why that matters more than the setup.

What call forwarding is and when to use it

Call forwarding (also called call diversion) reroutes an incoming call to a different number before it reaches you. The caller dials your usual number; the network quietly passes the call on to wherever you have told it to go.

Common reasons to forward calls:

• You are out of the office and want work calls to reach your mobile.
• You are on holiday and want calls handled by a colleague.
• You run a small business from a landline but spend the day on site.
• You want missed or busy calls to land somewhere useful instead of dead air.

There are two broad types. Unconditional forwarding sends every call straight on, so your phone never rings. Conditional forwarding only kicks in under specific conditions — when you do not answer, when the line is busy, or when your phone is switched off or out of signal. Conditional forwarding is usually what you want, because your phone still rings normally and only the calls you would otherwise miss get diverted.

The quick way: UK GSM codes

The fastest method on any UK mobile is a GSM short code. These are typed into your dialler exactly like a phone number, then you press call. They work on most UK networks — EE, O2, Vodafone and Three — and the change is stored on the network, not the handset, so it sticks even if you restart your phone.

Replace <number> with the full number you want calls sent to (including the leading 0).

So to send every call to 07700 900123, you would dial **21*07700900123# and press call. To stop it again, dial ##21#. If you ever lose track of what is set, ##002# clears the lot.

A practical setup for a small business is to leave your phone ringing as normal but catch the calls you would otherwise miss: set **61*<number># (no answer), **67*<number># (busy) and **62*<number># (unreachable) all pointing at the same backup number.

The menu method on iPhone and Android

If codes feel fiddly, both major phone systems have a settings screen for unconditional forwarding.

iPhone

1. Open Settings.
2. Tap Phone.
3. Tap Call Forwarding.
4. Toggle it on.
5. Enter the number you want calls forwarded to.

A small forwarding icon appears in your status bar while it is active, so you do not forget it is on. Note that iPhone's menu only handles "forward all calls" — for conditional forwarding (no answer, busy) you still need the GSM codes above.

Android (stock dialler)

1. Open the Phone app.
2. Tap the three-dot menu.
3. Go to Settings.
4. Tap Calling accounts (or Calls).
5. Tap Call forwarding.
6. Choose Always, When busy, When unanswered or When unreachable.
7. Enter the number and save.

Android's menu is more flexible than iPhone's because it exposes the conditional options directly. Exact wording varies a little by manufacturer (Samsung, Google Pixel, etc.), but the path is broadly the same.

Forwarding a BT or landline phone

Landline diverts work much like mobile codes. On a BT line:

• Set a divert: dial *21*<number># and wait for the confirmation tone.
• Cancel the divert: dial #21#.

For example, *21*07700900123# sends your landline calls to that mobile.

One caveat: BT's Call Diversion can be a chargeable feature depending on your plan. Some tariffs include it; others bill it as an add-on or charge for the diverted leg. Check your tariff before you rely on it, especially if you are diverting a high volume of calls.

If you are weighing up landline options more broadly, our guide to the best small business phone system compares the realistic choices for a UK small business, and the UK area codes hub explains what your local number actually signals to callers.

Conditional forwarding: only divert what you'd miss

This is the part most people skip, and it is the most useful. Instead of forwarding everything, you forward only the calls that would otherwise go unanswered:

• No answer (**61*<number>#) — rings your phone first, diverts if you do not pick up within the network's timeout.
• Busy (**67*<number>#) — diverts only when you are already on a call.
• Unreachable (**62*<number>#) — diverts when your phone is off or has no signal.

Set all three to the same destination and your phone behaves completely normally — but no caller ever hits a dead end. For a business, that single change is the difference between catching enquiries and losing them.

What call forwarding costs

The pricing model is simpler than it looks:

• The original caller pays as if they had dialled you directly. Forwarding is invisible to them.
• You pay for the onward leg — the call from your phone to the forwarded number — at your normal rate.

For UK-to-UK forwarding (your phone to a UK landline or mobile), that onward leg is normally covered by your inclusive minutes, so in practice it often costs nothing extra. The exceptions to watch: forwarding to non-geographic or premium numbers, forwarding to international numbers, and BT Call Diversion on tariffs where it is a paid feature.

The catch: forwarding still needs someone to answer

Here is the limitation no GSM code fixes. Forwarding moves a call — it does not answer it. Whatever sits at the other end still has to pick up, or the call fails just the same.

Forward to a mobile that is already on another call, and the caller gets your voicemail. Forward to a colleague who is driving, and it rings out. Forward to voicemail deliberately, and many callers simply hang up — the cost of missed calls is one of the most underrated leaks in a small business, because a missed call is usually a missed customer who rings a competitor next.

So forwarding solves routing. It does not solve answering. For a one-person business or a team that is often hands-busy, that gap is where the value leaks out.

This is where forwarding to an AI virtual receptionist beats forwarding to voicemail or an already-busy mobile. You set the same diverts as above, but point them at a number that always answers. Orval picks up 24/7 in your business name, takes a message, captures the caller's details, and can book appointments straight into your calendar — for a fixed price from £19.99/month, with no per-minute fees. The caller gets a real conversation instead of a beep, and you get the enquiry written up rather than lost.

You do not have to choose forwarding or a receptionist. You use forwarding as the plumbing, and put something at the far end that actually answers.

Quick reference

• Forward all calls: **21*<number># — cancel ##21# — check *#21#
• No answer: **61*<number># — cancel ##61#
• Busy: **67*<number># — cancel ##67#
• Unreachable: **62*<number># — cancel ##62#
• Cancel everything: ##002#
• iPhone: Settings → Phone → Call Forwarding
• Android: Phone app → ⋮ → Settings → Calls → Call forwarding
• BT landline: set *21*<number>#, cancel #21#

Set the codes in a minute, and decide what you actually want answering at the other end. That second decision is the one that matters.

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Frequently Asked Questions

What is the code to forward all calls on a UK mobile?

Dial **21*<number># and press call, replacing <number> with the phone number you want calls sent to. To cancel, dial ##21#. To check whether forwarding is on, dial *#21#. These GSM codes work on most UK networks including EE, O2, Vodafone and Three.

How do I divert calls to my mobile?

On a mobile, dial **21* followed by your other number and #, then press call. On a BT landline, dial *21* followed by the mobile number and #. The original caller pays as if calling your normal number; you pay for the onward leg at your usual rate, which is normally within inclusive minutes for UK numbers.

Does call forwarding cost money?

Usually you pay for the onward leg — the call from your phone to the forwarded number — at your normal rate. Diverting to a UK landline or mobile from a UK phone is normally covered by inclusive minutes. BT's Call Diversion can be a chargeable add-on depending on your tariff, so check your plan.

How do I cancel all call diversions at once?

Dial ##002# and press call. This clears every type of diversion — all calls, no answer, busy and unreachable — in one go. You can also cancel each type individually, for example ##21# for all-call forwarding or ##61# for no-answer forwarding.