Local numbers
The 029 Area Code: Cardiff Phone Numbers
029 is the telephone area code for Cardiff. Like London's 020, it is a short 3-digit code followed by an 8-digit local number — so a Cardiff number looks like 029 XXXX XXXX. The familiar "02920" is not the code: the 20 belongs to the local number.
ONSIM puts a Cardiff 029 number on your existing mobile from £5/month + VAT — no app, no VoIP, no desk phone required.
Understanding the 029 area code
The 029 code covers Cardiff and Penarth. Nearby Barry (01446) and Newport (01633) have their own codes, so an 029 number is instantly recognisable as the Welsh capital.
Cardiff dialled 01222 until the Big Number Change of April 2000, when the code became 029 and 6-digit local numbers gained a 20 prefix to make 8 digits — 01222 XXXXXX became 029 20XX XXXX. That conversion is why most established Cardiff numbers begin 029 20, and why many people mistakenly treat "02920" as the code. Newer ranges begin 029 21 and 029 22, and all are equally valid Cardiff numbers.
To dial, use 029 plus the 8-digit local number from anywhere in the UK, or +44 29 from abroad. ONSIM can provide 029 numbers across the available ranges, subject to current availability.
Why Cardiff businesses choose a local number
As the capital of Wales, Cardiff concentrates a lot of commercial life: government and public-sector supply chains, a well-established broadcast and creative production sector, growing professional services around Central Square and Cardiff Bay, and a strong student and visitor economy.
An 029 number on a mobile gives businesses across that mix a professional Cardiff identity — without an office phone system, and without publishing a personal mobile number.
How it works with ONSIM
ONSIM routes your incoming 029 calls to your mobile at network level — not through an app that depends on Wi-Fi or data. That means reliable call quality wherever you are.
Start with Virtual Landline for inbound calls from £5/mo, then upgrade to Landline SIM when you want outbound calls to display your Cardiff number too.
Who uses a Cardiff virtual landline?
An 029 number works for any business that wants a presence in the Welsh capital while staying flexible. Common use cases include:
Media & creative businesses
Cardiff's production companies, agencies and freelancers move between studios, sets and client offices. A virtual landline keeps one professional Cardiff number constant through all of it.
Professional services
Consultants and firms serving public-sector and corporate clients in the capital use an 029 number to signal a genuine Cardiff presence, even when the team works remotely.
Trades serving Cardiff & the Vale
Plumbers, electricians and home-service businesses covering Cardiff and Penarth win more local calls with a recognisable 029 number — answered on the mobile already in their pocket.
New number or port your existing one
Need a fresh 029 number? ONSIM can get you started quickly. Already have a Cardiff landline? Number porting may be possible — contact us to check eligibility before switching.
Virtual Landline vs Landline SIM
Virtual Landline (from £5/mo): inbound calls only, rings your current mobile, simple setup with no hardware.
Landline SIM (from £10/user/mo): inbound and outbound with your Cardiff number displayed, native mobile experience.
We cover more than Cardiff
ONSIM supplies local business numbers across 650+ UK area codes. If you need coverage in multiple cities or want to compare options nationally, we can help.