02921 Area Code
The dialling code for Cardiff: what 02921 numbers are, who holds them, and what to do about a call you don't recognise.
What Is the 02921 Area Code?
Cardiff landline number. 02921 numbers are UK landline numbers in the 029 area code, which covers Cardiff. Internet phone services can use them too, so a caller is not necessarily there.
Who was the range allocated to?
Ofcom has allocated 02921 numbers to 69 providers. The largest holders are Gamma Telecom Holdings Limited, Vodafone Ltd (C&W) and Digital Space Group Limited.
Numbers can be moved (ported) between networks, so the network a caller uses today may not be the one Ofcom allocated the block to. The allocation does not identify the person or business using a number.
Had a call from a 02921 number you don't recognise?
We can't tell you who called: an area code only shows the type of number and the provider Ofcom allocated the range to.
- Don't call back in a hurry, even if a message says it's urgent. Never give bank details or security codes on a call you didn't expect.
- Block the number from your phone's recent calls list.
- Forward scam texts free to 7726. Report unwanted marketing calls to the ICO, and see Ofcom's advice on scam calls.
- Register your number with the Telephone Preference Service to opt out of sales calls.
About the 02921 Range
| Number type | Cardiff landline number |
|---|---|
| Area | Cardiff |
| Part of | the 029 area code (Cardiff) |
| Number format | 029 21XX XXXX |
| Allocated by Ofcom | 82% of the range, to 69 providers |
| First allocation on record | 9 August 2005 |
| Most recent allocation | 10 July 2026 |
Largest holders of 02921 numbers
| Provider (as allocated by Ofcom) | Share of range | First allocated |
|---|---|---|
| Gamma Telecom Holdings Limited | 4% | 18 January 2010 |
| Vodafone Ltd (C&W) | 4% | 20 June 2013 |
| Digital Space Group Limited | 3% | 9 June 2008 |
| TalkTalk Communications Limited | 3% | 14 July 2006 |
| Virgin Media Limited | 3% | 29 July 2009 |
| Colt Technology Services | 2% | 11 May 2006 |
63 more providers hold smaller blocks.
Allocation data: Ofcom numbering data, as published 28 October 2026.
Get Your Own 02921 Number
Want a Cardiff number for your business? DigitalNumbers gives you one that rings on your existing mobile, with its own app, voicemail and WhatsApp Business support.
- Make and receive calls using our included app
- Forwards calls to your existing mobile
- Works with WhatsApp Business
- Includes professional voicemail
- Lets you set working hours
Common Questions About 02921 Numbers
Where is the 02921 area code?
02921 numbers are UK landline numbers in the 029 area code, which covers Cardiff. Internet phone services can use them too, so a caller is not necessarily there.
Is 02921 a mobile number?
No. 02921 is a landline (geographic) area code for Cardiff. UK mobile numbers start with 07.
Who does the 02921 range belong to?
Ofcom has allocated 02921 numbers to 69 providers. The largest holders are Gamma Telecom Holdings Limited, Vodafone Ltd (C&W) and Digital Space Group Limited. Numbers can be moved (ported) between networks, so the network a caller uses today may not be the one Ofcom allocated the block to. The allocation does not identify the person or business using a number.
Who called me from a 02921 number?
We can't tell you who called. An area code only shows the type of number and which provider Ofcom allocated the range to. If you don't recognise a 02921 number, don't call back in a hurry, and never give out bank details or security codes on a call you didn't expect.
Block the number from your phone's recent calls list. Forward scam texts free to 7726, report unwanted marketing calls to the ICO, and see Ofcom's advice on scam calls.