Mobile Landline SIM


What is a mobile landline SIM?



A mobile landline SIM (such as our ONSIM Landline SIM) is a SIM (Subscriber Identity Module) card that can have a UK landline number (starting 01, 02, 03 or 08) as well as a UK mobile number (starting 07). This offers a choice of number that is displayed to the callee on an outbound call. Mobile landline SIM’s are typically used by businesses who want to present a professional image to their customers but where it’s not feasible or desirable to install a traditional fixed/cable landline. Other (but not all reasons) someone would choose to use a mobile landline SIM are;

  • Mobile Working - being able to answer and make calls from your landline on the move

  • Cost Savings (for both the owner and those calling the landline)

  • Separation of business and personal numbers for privacy

  • Monitoring usage / staff

  • Scalability - multiple users can share the same number

  • Redundancy for other phone solutions

  • Where internet speeds aren’t stable enough for VoIP (Voice Over IP)

  • Time sensitive setup - no installation means they can be set up instantly

  • Compliance requirements

Because of their deep integration into our unique cloud based mobile PBX (MPBX) mobile landline SIM’s also have a wide range of other features normally only found on traditional office phone systems such as call recording, hold and transfer, group features and more. These converged services allow greater flexibility and mobility of existing workforces giving businesses “The best bits from your regular office phones but with the freedom of a mobile”.

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Mobile Landline SIM

How do mobile landline SIM’s compare to other solutions?

There are lots of providers in the UK that claim to offer ‘mobile landlines’ or 'virtual landlines'. These fall into one of two categories; ‘Diverts' and ‘Apps'.  As you can see below, neither solution truly offers the simplicity or power that you get with a mobile landline SIM.


Landline Diverts / Virtual Landlines

This solution involves a phone provider supplying a virtual or hosted landline number that is on a permanent divert to a mobile number of your choice. There are a couple of issues with this approach:

  • The divert is always chargeable, meaning that you will be either capped to a certain number of inbound minutes per month or you will pay by the minute to answer your calls. What happens when you run out of inbound minutes? Blocked calls and extra charges.

  • If you are using a personal mobile it might also be hard to distinguish between business and personal calls leading to confusion, missed calls and embarrassing situations.

  • Voicemail can also be a big issue with virtual landlines and diverts as often a personal voicemail kicks in before the system voicemail giving away to your caller that this call is on divert.

  • Possibly the biggest issue with virtual landlines is what if you miss the call and want to return it? If you call back from your mobile the caller has your personal mobile and won’t call your landline again. If you call back and withhold your number they might not recognise or answer it (lots of customers we survey tell us they do not answer withheld numbers). Some customers might consider this to be unprofessional and cast doubts around the size and legitimacy of your organisation - there is a real stigma around mobile and landline numbers in the UK.

  • Another question to consider is "What if you aren’t the only one that answers calls?” If you need a group of people to share the burden of answering calls virtual landlines often won’t scale very well past one or two users.

Although there are some drawbacks of using a virtual landline forwarded to your mobile, they are often a good start for a company phone line. If you already have a virtual landline or are looking for something a bit more feature rich, why not take a look at our Landline SIM.

Virtual Landline forwarding
landline app

Mobile Landline Soft-phone Apps

Essentially these solutions are 'soft-phone’ (software phone) apps installed on a smartphone that connect over a data connection to a VoIP system and allow you to make and receive calls. This solution is touted as the future of unified communications and it sounds great. Unfortunately, in the real world WiFi and Data networks simply don’t provide a consistent enough connection for high quality calls. Buffering and dropped calls will make you sound like you’re underwater and frustrate both you and your customers and within a short time you will give up on it. Furthermore, you can only make and receive the calls when you have the app on or on background refresh which will deplete your mobile phone battery very quickly.

Although there are some drawbacks to using mobile apps, largely due to current mobile data limitations, they work ok alongside our mobile landline SIM’s. Our customers often use soft phone apps to cost effectively make and receive calls on their landline when they are outside the EU or for remote workers. If you want to find out more about our Soft-phone VoIP app please email


The Benefits of a mobile landline SIM

We’ve looked at different types of mobile landline solutions there are out there but what about the mobile landline SIM? If you’re looking for the best in class solution for your mobile landline this is how they can benefit you and your business.

  • No charge for receiving calls and no caps for inbound calls.

  • Keep your business calls and personal calls separate.

  • Make and receive calls on your landline number but from your mobile.

  • Your business number can be shared with all the users on your system for both inbound and outbound calls – one business number across all mobiles and desk phones.

  • Advanced Features such as groups, advanced voicemail, FCA compliant call recording, hold and transfer, hold music and more.

  • Calls are placed over the regular GSM mobile network rather than relying on unpredictable data or WiFi connections.

  • Access EE and O2 masts to address coverage issues and for redundancy

  • Single bill for your business mobiles and business landlines.

  • Pair with IP phones for seamless call handling in and out of the office and one voicemail, call recording and extension number.

  • Can be used on any mobile phone – works on smart phones and feature phones.

  • Cost effective - no line rental and no installation fees.

  • Perfect redundancy solution to back up your office phones in case of power or internet failure.

  • Fast set up - no waiting around for cable landlines to be installed.

  • Use your phones native app to make and receive calls

  • Record calls for compliance

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Landline SIM Icon

Mobile Landline SIM Features

Our mobile landline SIM's aren't just a replacement for your business mobiles - they are a full featured office phone system you can put in your pocket and take anywhere. Take a look at some of the great features you get with our mobile landline SIM's:

Make & Receive calls over a landline
Transfer calls and play hold music
Record calls & messages at carrier level
All the services you expect from a mobile plus loads more
Our SIM's use EE as a primary carrier but they can be switched to O2 to resolve coverage issues or for redundancy. All through a Single SIM.
Route calls based on customisable time schedules
Get voicemails delivered via email
Divert your calls via our online portal
Direct callers based on customisable menus
Share numbers across multiple SIMs for both inbound & outbound calls

These are just some of the great features of an ONSIM Landline SIM - call us now to find out more on +44333 880 4008


How our mobile landline SIM’s work

Our Mobile Landline SIM’s are all about taking the best parts of your office phones with you wherever you go. We do this by cleverly routing your calls through EE and O2's networks and onto our hosted mobile phone system (MPBX). From here, the call can behave just like you made it from a landline and means we can offer incredibly low cost calling and all the features you have come to expect from your regular office phones.

ONSIM Network Overview

The Mobile Landline SIM

If you would like to find out more about our Mobile Landline SIM’s you can watch our ONSIM video or download the ONSIM Mobile Landline SIM Overview guide by clicking the link below.

If you have any other questions you can contact one of our experts at

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