How to divert calls from a landline to a mobile (UK)

Want your home or office landline to ring through to your mobile when you are out? Diverting (or forwarding) a landline to a mobile is straightforward, and on most UK lines you can set it up in seconds using a simple keypad code — the classic ***21* sequence. This is invaluable if you run a small business from a landline, are waiting for an important call while away from the house, or simply want to stop missing calls to the home number. This guide explains exactly how to divert a UK landline to a mobile on BT, Sky and Virgin Media**, the codes to set, check and cancel a divert, what it costs (the part that catches people out), and the pitfalls to avoid so you do not end up with a surprise bill or calls going to the wrong place.

#How to divert a landline to a mobile (the codes)

On the great majority of UK landlines, call diversion is controlled by standard 'star codes' you dial straight from the phone. To divert all incoming calls to your mobile, pick up the landline and dial *21* followed immediately by the full mobile number, then #, and press call — for example *21*07700900123#. You should hear a confirmation tone or message. From then on, every call to your landline rings your mobile instead. To cancel the divert and have calls ring the landline again, dial #21# and press call. To check whether a divert is currently set, dial *#21#. These three codes — set, cancel, check — cover the everyday needs, and because they are standard across most providers, they work the same way on most BT, Sky and Virgin Media home lines.

#Diverting only some calls (no answer or busy)

You do not have to send *every* call to your mobile. Often the more useful setup is a conditional divert: the landline rings as normal, and calls only forward to your mobile if you do not pick up, or if the line is engaged. To divert calls only when there is no answer (after the landline has rung for a while unanswered), dial *61* followed by the mobile number and #. To divert calls only when the line is busy, dial *67* followed by the mobile number and #. These conditional diverts are ideal for a home or small office where you want to answer on the landline when you are there, but catch the call on your mobile when you are not — without forwarding calls you would have answered anyway. Each conditional divert has its own cancel code (#61# and #67#), and you can combine them, for instance forwarding on both no-answer and busy. This flexibility is one of the underrated benefits of landline diversion: you can tune exactly which calls follow you.

#What does diverting a landline cost?

This is the part that surprises people, so it is worth being clear: a divert is usually not free. When a call is diverted from your landline to your mobile, your line provider treats the forwarded leg as a call *you* are making from the landline to the mobile number — so you typically pay for that, at your landline's rate for calling a mobile, for the duration of each diverted call. If your landline plan includes calls to mobiles, the cost may be covered; if not, every diverted call that someone makes to your landline could be billed to you as a landline-to-mobile call. On top of that, some providers treat call diversion as a chargeable feature or add-on that must be enabled on the account, rather than something available by default. The practical upshot: before relying on diversion heavily, check (a) whether your provider charges to enable the feature, and (b) how the diverted legs are billed on your plan. For occasional use it is usually trivial; for a business diverting a high volume of calls all day, the cost can add up, so factor it in.

#Provider specifics: BT, Sky and Virgin Media

The standard *21* codes work on most lines, but there are provider nuances worth knowing. On BT, call diversion is a feature on most lines and the star codes generally work; BT also offers managed call-diversion options and, on some products, online or app control, and the feature may be included or chargeable depending on your package — check your BT plan. On Sky home phone lines, the same *21*, #21# and conditional codes typically apply, and diversion may be part of your calls package or an add-on. On Virgin Media, call divert is likewise generally available via the star codes, sometimes requiring the feature to be active on your account. Because the exact availability, wording and charges differ by provider and package — and because some newer 'digital voice' (internet-based home phone) services manage diversion through an online account or app rather than star codes — the safest approach is to try the standard codes first, and if they do not work, check your provider's help pages or account settings for how diversion is enabled on your specific line. If you have moved to a digital landline, look in your provider's online account or app, where call forwarding is often a simple on-screen toggle.

#When diverting a landline is useful

Landline diversion solves a range of everyday problems. For small businesses and sole traders who advertise a landline number, diverting it to a mobile means you never miss a customer call when you are out on a job or away from the desk — the professional landline number stays on your marketing, while the calls follow you. For households, it is handy when you are away for a few days and want to catch any calls to the home number, or for an elderly relative whose landline calls you want routed to your mobile so you can help. It is also useful as a continuity measure: if you are between offices, moving home, or your broadband-based phone might be unreliable, diverting ensures calls still reach you. And the conditional (no-answer) divert is perfect for simply reducing missed calls — the landline rings first, and anything you miss rolls to your mobile. In all these cases, the landline number that callers know stays the same; only where the call ends up changes, which is exactly the flexibility most people want.

#Pitfalls and how to avoid them

A few traps catch people out with landline diversion, and they are easy to avoid once you know them. The first, covered above, is cost — forgetting that you pay for the diverted leg and being surprised by the bill; the fix is to check your tariff and use conditional diverts to forward only the calls you would otherwise miss. The second is forgetting a divert is on: if you set an all-calls divert and forget, your landline will appear 'dead' (it never rings) because everything is going to your mobile — dial *#21# to check, and #21# to cancel if you are puzzled by a silent landline. The third is diverting to the wrong number: always enter the full mobile number carefully, and test the divert by calling your landline from another phone to confirm it rings the right mobile. The fourth is assuming diversion is free or always available — some providers charge or require it to be enabled, so confirm before you depend on it. Finally, remember that a divert forwards *incoming* calls only; it does not change the number shown to the caller, and it does not affect calls you make. Avoid these and diversion is a reliable, set-and-forget convenience.

#Diverting, caller ID and unwanted calls

A practical question is what happens to caller ID when a call is diverted: when a landline call forwards to your mobile, your mobile generally shows the original caller's number (where available), so you can still see who is calling before you answer — the divert passes the call through rather than hiding the caller. That is useful, because it means you can apply the same judgement to a diverted call as to any other: if an unfamiliar number rings through, you can look it up before answering or calling back, exactly as you would normally, using the routine in our who called me? guide. One side effect of diverting a landline to a mobile is that nuisance and scam calls to the landline will now reach your mobile too, so if your landline gets a lot of junk calls, it is worth tackling those at source — see our block a number on a landline guide — before or alongside setting up a divert, so you are not simply forwarding the nuisance to your pocket. Diversion is a tool for catching the calls you want; pairing it with sensible blocking keeps the ones you do not want from following you.

#Diverting for a small business

For sole traders and small businesses, diverting a landline to a mobile is one of the simplest ways to look professional while never missing work. The setup most businesses want is this: advertise and keep your established landline number (which looks more settled and local than a mobile to many customers), but divert it to your mobile so you can answer wherever you are. The decision worth making deliberately is *which* divert to use. An all-calls divert (*21*) means every business call rings your mobile, ideal if no one is ever at the landline; a no-answer divert (*61*) means the landline rings first — useful if someone is sometimes in the office — and only unanswered calls roll to your mobile. Many small businesses combine a no-answer and busy divert so that calls are caught whether the line rings out or is engaged. Bear in mind the cost point especially here: a business taking a high volume of calls all day will pay for each diverted leg, so check whether your business tariff includes calls to mobiles, and weigh diversion against a more capable business phone system if your call volume is large.

It also pays to think about how diversion fits with the rest of your phone setup. If you divert to your mobile, you will want a sensible voicemail greeting on the mobile (or on the landline) so that calls you genuinely cannot take are handled professionally rather than ringing out. You may want to know which network your number sits on and how it presents to customers — our UK mobile networks by 07 prefix guide explains the ranges. And if your landline attracts a lot of nuisance and sales calls, diverting will send those to your mobile too, interrupting you during work; tackling them with the blocking measures in our block a number on a landline guide first means you forward genuine customers, not junk. Used thoughtfully, diversion lets a one-person business present a stable landline front while staying as mobile as the work requires — and the whole thing is controlled by a couple of keypad codes you can change in seconds as your day demands.

#Digital landlines and the future of diversion

It is worth a word on the shift to digital voice (internet-based home phone), because it changes how diversion is set up for a growing number of households. As traditional copper phone lines are retired in favour of services that route calls over your broadband, the home phone increasingly plugs into a router or is managed through an online account or app rather than the old exchange. On these services, the classic *21* star codes may or may not work, and call diversion is often instead a simple on-screen toggle in the provider's app or account settings, where you enter the mobile number to forward to and switch it on. If you have moved to a digital landline and the star codes do not seem to take effect, that is where to look. The good news is that app-based control is usually easier and clearer than remembering codes, and it often lets you set up conditional diverts, schedules and voicemail handling from one screen. The underlying capability — sending your landline calls to your mobile — remains, and is arguably more flexible than ever; only the method of switching it on has moved from the keypad to the screen. As with the choice of network and plan generally, it is worth knowing what your provider offers; our best mobile network in the UK guide is a useful companion when you are reviewing your overall phone setup.

#Diverting while away, moving home, or in an emergency

Beyond the everyday small-business and missed-call uses, landline diversion is genuinely valuable in a few specific situations that are worth planning for. When you go away for a holiday or a longer trip, setting an all-calls divert to your mobile means you stay reachable on your home number without giving anyone your mobile, and you can cancel it the moment you are back with #21#. When you are moving home, diversion bridges the gap: if your new line is not active yet, or you want callers to your old number to still reach you during the transition, a divert keeps you contactable while everything settles. For an elderly or vulnerable relative, diverting their landline to your mobile (with their agreement) can route their incoming calls to you when they are in hospital, on holiday, or simply need help managing calls — a quietly useful safeguard. And as a business-continuity step, if a flood, power cut or broadband outage might take out a premises phone, having a divert ready to point the number at a mobile keeps the line working through the disruption. In each case, the strength of diversion is that the number people know stays the same, and you control where it lands with a couple of codes.

A couple of practical reminders make these uses smoother. Test any divert by calling the landline from another phone before you rely on it, so you know it is pointing at the right mobile. Note that diverting does not change the caller's experience — they dial the same number and pay the same — so there is nothing for them to do or notice. Keep in mind the cost of the diverted legs, especially for a long trip with lots of incoming calls, and consider a no-answer divert if you would rather only catch what you miss. And remember to cancel the divert when you no longer need it, both to avoid a silent landline and to stop paying for forwarded calls; *#21# tells you whether one is still active. With those small habits, diversion becomes a dependable tool you reach for whenever life takes you away from the landline — confident that the calls will follow you, and that you can switch it off the instant you are back at your desk.

It is also worth knowing the difference between the three divert types when you set one of these up, because choosing the right one avoids surprises. All-calls divert (*21*) sends everything to the mobile immediately and the landline never rings — ideal when you are away and want nothing missed. No-answer divert (often *61*) lets the landline ring first and only forwards if you do not pick up after a set number of rings, which suits a home office where you answer when you are there but want the overflow on your mobile. Busy divert (often *67*) forwards only when the line is engaged, useful if you take a lot of calls and do not want a second caller to hit a busy tone. You can even combine no-answer and busy diverts so the line behaves intelligently without sending everything away. Check the exact codes with your provider, because the all-calls *21* is universal but the conditional codes vary slightly between networks, and a quick test call confirms you have set the behaviour you intended before you depend on it.

#Bottom line

To divert a UK landline to a mobile, dial ***21* then the full mobile number then # from the landline, and press call; cancel with #21# and check with *#21#. For a smarter setup, use the conditional codes — *61* to forward only unanswered calls and *67* only when busy — so the landline rings first and you only catch what you would have missed. Remember that you pay for the diverted leg** (a landline-to-mobile call), and that some providers charge to enable the feature, so check your tariff. The standard codes work on most BT, Sky and Virgin Media lines, while newer digital-voice services often manage diversion through an app or online account. Test it by calling your landline, watch for a silent landline left on divert, and pair diversion with blocking nuisance numbers so you forward the calls you want, not the ones you don't. For diverting a mobile's own calls, see our forward or divert calls guide.