The basic structure of a UK mobile number

A British mobile phone number has 11 digits total, always starting with 07. The format looks like this: 07XXX XXXXXX, where X represents the remaining nine digits. The first four digits after the 07 (the part written as 07XXX) identify which network or mobile virtual network operator (MVNO) issued the number. The remaining seven digits are unique to your account.

When you write down a UK mobile number, you will see it formatted as 07XXX XXXXXX with a space in the middle, or sometimes as 07XXXXXXXXXX with no space. Both are correct. If you are sending the number internationally, you replace the leading 0 with +44, so it becomes +447XXX XXXXXX. The +44 is the country code for the United Kingdom.

The 07 prefix is what makes a number mobile rather than landline. Landlines in the UK start with different prefixes depending on the region — for example, London numbers start with 020, Manchester with 0161. Mobile numbers, by contrast, are not tied to a location.

Key Takeaways

  • UK mobile numbers have 11 digits and always start with 07, followed by nine more digits in the format 07XXX XXXXXX.
  • The four digits when ready after 07 identify which network issued the number, while the remaining seven digits are unique to your account.
  • When dialling from outside the UK, replace the leading 0 with +44 to get +447XXX XXXXXX.
  • The 07 prefix distinguishes mobile numbers from landlines, which use different regional prefixes like 020 for London or 0161 for Manchester.

How the network identifier works

The four digits after 07 — written as 07XXX — tell you which network originally issued the number. The major networks in the UK are Vodafone, EE (formerly Orange and T-Mobile), O2, and Three. Each network owns a set of number ranges. For example, some Vodafone numbers start with 07900, while some EE numbers start with 07911.

However, this does not mean the person using the number is still on that network. When you switch networks, you can keep your existing mobile number through a process called number porting. The original network identifier stays the same even after you move to a different provider. So a number starting with 07900 might have been issued by Vodafone but could now be used by someone on Three or any other network.

MVNOs — smaller companies that rent network access from the big four — also have their own number ranges. Giffgaff, for example, rents from O2 and has its own set of numbers. When you look up a number, the range tells you which network it was originally issued by, not necessarily which one the person is using now.

Dialling UK mobile numbers from abroad

If you are outside the UK and need to call a British mobile number, you must change the format. Remove the leading 0 and replace it with +44. So 07700 900000 becomes +447700 900000. The +44 is the international dialling code for the United Kingdom. You can also use 0044 instead of +44 if your phone does not support the plus symbol.

When you are inside the UK, always use the full 11-digit number starting with 0. When you are outside the UK, always use the +44 format. Mixing them up — for example, trying to dial +4407700 900000 — will not work because you are doubling the country code.

What the remaining seven digits mean

After the network identifier (07XXX), the final seven digits are unique to your specific account. These digits are assigned by your network in sequence as new customers sign up. There is no hidden meaning in these seven digits — they do not encode your location, your sign-up date, or any other information. They are straightforward a way to distinguish your number from every other number on that network.

This is different from landline numbers, where the digits after the area code sometimes indicate which exchange (local telephone office) serves that number. Mobile numbers have no such geographic meaning because they are not tied to a location.

Special mobile number ranges

Most UK mobile numbers follow the 07XXX XXXXXX pattern, but a few other prefixes exist for specific purposes. Numbers starting with 070 are used for personal numbers — a service where one number can ring multiple devices or locations. Numbers starting with 075 are used for machine-to-machine communication, typically for IoT (Internet of Things) devices rather than human users.

For everyday purposes, you will encounter 07 numbers. The 070 and 075 ranges are much less common and serve specialized functions. If someone gives you a number starting with 070, it works the same way as a regular mobile number when you call it, but it may be configured to ring in unusual ways.

How to identify a valid UK mobile number

A valid UK mobile number has exactly 11 digits and starts with 07. If a number has fewer or more than 11 digits, or starts with a different prefix, it is not a mobile number. You can check this yourself by counting the digits: 07XXX XXXXXX is always 11 digits total.

If you receive a number that looks like it might be a UK mobile but does not follow this pattern, it may be a landline, a non-geographic number (like a customer service line), or a number from a different country. Landlines in the UK are 10 or 11 digits depending on the area, and they start with 0 followed by a different prefix than 07.

Frequently Asked Questions

Can I keep my mobile number if I switch networks?

Yes, through a process called number porting. You can move your number to a different network while keeping the same 11-digit number. The original network identifier (the 07XXX part) will not change, even though you are now on a different provider. Your new network will handle the transfer, which usually takes a few working days.

Why do some UK mobile numbers start with different digits after 07?

The digits after 07 identify which network originally issued the number. Vodafone, EE, O2, and Three each own different ranges of numbers. However, because of number porting, the original network identifier does not tell you which network the person is currently using — only which one issued it.

What is the difference between 07 and 070 numbers?

Numbers starting with 07 are standard mobile numbers. Numbers starting with 070 are personal numbers, a service that lets one number ring multiple devices or locations. For most people, 07 is what you will encounter. The 070 service is optional and less common.

Do I need to include the +44 when texting a UK number from abroad?

Yes, use the +44 format for texts just as you would for calls. Replace the leading 0 with +44, so 07700 900000 becomes +447700 900000. Some messaging apps may handle this automatically if you have the contact saved, but typing it manually requires the +44 format.

Is there a way to tell where a UK mobile number is based?

No. Unlike landlines, which are tied to specific regions, UK mobile numbers have no geographic meaning. A 07 number could belong to someone in London, Edinburgh, or anywhere else in the UK. The only information the number format reveals is which network originally issued it, not the user's location.