UK Mobile Number Format — How UK Cell Phone Numbers Work
Every UK mobile phone number starts with 07 and contains 11 digits in total. Whether you need to call a UK mobile from overseas, save a number in international format, or understand which network a prefix belongs to, this guide covers everything you need to know about UK mobile number formatting.
The UK Mobile Prefix: 07
All UK mobile numbers begin with 07 when dialed domestically. This is how the UK numbering system distinguishes mobile phones from landlines (which start with 01 or 02) and other services.
A complete UK mobile number has 11 digits:
The first five digits (07 + three more) form the mobile prefix, and the remaining six digits are the subscriber number. The spacing convention is 07XXX XXXXXX, though 07XX XXX XXXX and 07XXXXXXXXX (no spaces) are also commonly seen.
Network Prefixes
When UK mobile numbers were first allocated, specific prefix ranges were assigned to each mobile network. While number portability (introduced in 1999) means people can keep their number when switching networks, the original allocations are still useful as a rough guide.
| Network | Common Prefixes | Example Number |
|---|---|---|
| O2 (Telefonica) | 074, 075, 07624 |
07412 345678 |
| Vodafone | 076, 077 |
07700 900123 |
| EE (BT Mobile) | 073, 0744, 0745 |
07345 678901 |
| Three (Hutchison) | 078, 079 |
07891 234567 |
| Virtual operators (MVNOs) | Various — use host network ranges | Varies |
Important: Number portability
Since users can port their number to any network, you cannot reliably determine someone's current carrier from their mobile number prefix. A 077 number that was originally Vodafone may now be on EE or Three.
International Format: +44
To write a UK mobile number in international format, drop the leading 0 and add +44:
The +44 is the UK's country code. The plus sign (+) represents the international dialing prefix, which varies by country (011 in the US, 00 in most of Europe, 0011 in Australia).
For database storage, use E.164 format with no spaces: +447700900123. This is the standard for SMS APIs, CRM systems, and international telecommunications.
Texting UK Mobiles from Abroad
To send an SMS to a UK mobile number from another country:
- Save the number in +44 format — replace the leading 0 with +44
- Send the message normally — your phone handles the international routing
- Use messaging apps — WhatsApp, iMessage, Telegram, and Signal all work with +44 numbers and route over the internet instead of SMS
| From Country | Dialing Method | Example |
|---|---|---|
| United States / Canada | 011 44 + number |
011 44 7700 900123 |
| Europe (most) | 00 44 + number |
00 44 7700 900123 |
| Australia | 0011 44 + number |
0011 44 7700 900123 |
| Any (mobile) | +44 + number |
+44 7700 900123 |
Virtual UK Mobile Numbers
Virtual UK mobile numbers are phone numbers that are not tied to a physical SIM card. They work over the internet (VoIP) and can be used for receiving calls and SMS from anywhere in the world.
Common uses:
- Privacy — use a virtual number instead of your personal number for online signups, dating apps, or marketplace listings
- Business — give customers a UK mobile number to call, even if your team is based overseas
- Travel — receive UK calls and texts while abroad without paying roaming charges
- Testing — developers use virtual numbers to test SMS verification flows in applications
Providers like TextNow, Hushed, and Google Voice (limited UK support) offer virtual numbers. Some UK banks and services may not accept virtual numbers for SMS verification due to fraud prevention policies.
Special UK Mobile Ranges
- 07700 900000 to 07700 900999 — Ofcom reserved range for drama, fiction, and testing. These numbers are guaranteed to never be assigned to real subscribers
- 07624 — Isle of Man mobile numbers (Crown dependency, uses UK +44 country code)
- 07797, 07829, 07937 — Jersey and Guernsey mobile numbers (Channel Islands)
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Frequently Asked Questions
Yes, all UK mobile phone numbers start with 07 when dialed domestically. In international format, the leading zero is dropped and replaced with +44, so a UK mobile becomes +44 7XXX XXXXXX. The only exception is the Isle of Man prefix 07624, which is technically a Crown dependency but uses the UK numbering plan.
The prefix after 07 originally indicated the mobile network (e.g., 077 for Vodafone, 079 for Three). However, since mobile number portability was introduced in 1999, users can keep their number when switching networks. So the prefix is no longer a reliable way to identify the current carrier.
To text a UK mobile number from abroad, use the international format: replace the leading 0 with +44. For example, if the UK number is 07700 900123, save it as +447700900123 in your phone. Most smartphones handle the + prefix automatically when sending international SMS or messages through WhatsApp and similar apps.