Mobile phone numbers
07521 numbers are for mobile phones in the United Kingdom.
All UK 07 numbers are for mobiles, pagers and personal numbering.
Which network uses 07521 numbers?
07521 numbers are officially allocated to O2 for mobile phone services.
All 07521 numbers will have originally been issued to customers by O2. However, customers are free to take their number with them when they change networks which means that an 07521 number is not a reliable indicator of which network a phone is currently connected to.
These are normal mobile numbers and will usually be charged at standard rates.
Formatting an 07521 number
There is no set format for UK mobile phone numbers, but the commonest format is: 07521 xxxxxx
For international callers, use: +44 7521 xxxxxx