UK mobile numbers
07921
Who called you from 07921?
A 07921 number is a UK mobile number. The prefix tells you which network originally issued it, though the owner may have moved networks since (UK numbers are portable). It says nothing about who is holding the phone.
Was it a scam?
The code alone can't tell you, and anyone who says otherwise is guessing. What settles it is the call itself: a genuine organisation survives you hanging up and ringing back on the number from its website or your paperwork. If the caller wanted money, bank details, one-time codes or remote access to your computer, treat it as hostile.
What to do now
- Missed call, no voicemail? Don't ring back numbers you don't recognise. Anything important comes back properly.
- Suspicious call: forward the number and what was said to 7726, free on every UK network.
- Lost money or gave away details: Action Fraud, 0300 123 2040 (Police Scotland on 101 in Scotland), and your bank on the number on your card.
- If a caller claims to be from a government department, ring the department back on its official number, which ContactNumbers lists with the source.
- Full walkthrough in the report a call guide.
UK mobile numbers: what the register shows
07921 is a UK mobile prefix. Ofcom's register shows 10 allocated blocks held by 1 operator. Telefonica UK Limited holds the most, with 10 of the 10 allocated blocks. Data retrieved 2026-10-22.
- Allocated blocks
- 10
- Operators
- 1
- Free or protected
- 0
- Share allocated
- 100%
Which companies hold 07921 numbers
Ofcom allocates numbers to phone companies in blocks. These are the operators holding the most 07921 blocks. The company that was issued a number often supplies it onward to a business or reseller, and UK numbers can be ported between networks, so read this as where the number started, and a strong hint rather than proof of who serves it today.
| Operator | Blocks held | Share of allocated |
|---|---|---|
| Telefonica UK Limited | 10 | 100% |
What it costs to call 07921
Standard mobile rate
Calls to this prefix are charged like any UK mobile call and come out of inclusive minutes on almost every plan.
Inclusive minutes: Yes, on almost every UK plan. See the full UK call charges guide.
Questions people ask about 07921
What is a 07921 number?
07921 is a UK mobile prefix. 1 operator holds number blocks in this range according to Ofcom's allocation data.
Who called me from 07921?
A 07921 number is a UK mobile number. The prefix tells you which network originally issued it, though the owner may have moved networks since (UK numbers are portable). It says nothing about who is holding the phone.
How much does it cost to call 07921 numbers?
Standard mobile rate. Full details in the cost section above.
Is a call from 07921 a scam?
The code alone can't tell you. Most calls from 07921 numbers are legitimate, but scammers can dial from, or pretend to dial from, any range. Never hand over passwords, PINs or remote computer access to an inbound caller. If in doubt, hang up and call the organisation back on the number printed on its website or your paperwork.
How do I report a nuisance or scam call?
Forward scam call details to 7726 (free, all UK networks), report fraud to Action Fraud on 0300 123 2040, and report persistent nuisance calls to the ICO. Our report a call guide walks through each route.
Source: Ofcom telephone numbering allocation data, retrieved 2026-10-22 and reproduced with acknowledgement under Ofcom's re-use terms. Figures describe number blocks, and a block being allocated to an operator says nothing about any individual caller. Last verified by a human on 2026-10-22.