Local numbers
020 London Business Numbers
Get a London business number and answer calls on your mobile without relying on a VoIP app or traditional office line.
An 020 number can help your business look more established in London while keeping your setup mobile-first and simple.
Why choose a London number?
If you serve London clients, a 020 number can create a stronger local presence and look more credible than a personal mobile number.
That matters for consultants, service businesses, agencies, trades and mobile-first teams that want to feel more established in the capital.
Use it on your mobile
With ONSIM, your London number can ring on your existing mobile. Start with Virtual Landline for a simple inbound setup or move up to Landline SIM if you want outbound caller ID too.
Why London numbers start 0203, 0207, 0208 and 0204
London has one area code: 020. The extra digit people often focus on, such as the 3, 4, 7 or 8, is the start of the local number rather than a separate area code.
Historically, London was split into older codes for inner and outer areas. When those codes were brought together under 020, the familiar 7 and 8 prefixes stayed in place at the start of the local number. Later, 0203 and 0204 ranges were introduced to create more capacity as demand for London numbers increased.
In practice, that means businesses may be offered London numbers in several valid sub-ranges. ONSIM can provide London numbers across the main ranges, including 0203, 0204, 0207 and 0208, subject to current availability.
Local credibility
A London number can make your business feel closer to London-based customers even if you work flexibly or remotely.
No app needed
Calls can ring on your mobile without forcing you into a softphone app workflow.
Upgrade path
Start simple, then move to Landline SIM if you want a more complete mobile business calling setup.
New number or port your existing one
If you want a fresh London number, ONSIM can help you get started quickly. If you already have a 020 number, porting may be possible too.
That means you can keep brand continuity while modernising how your business answers calls.
Virtual Landline vs Landline SIM
Virtual Landline is the easier low-cost starting point if you mainly want inbound calls on mobile.
Landline SIM is the better fit if you also want outbound calls to show your London number.
We don’t just cover London
ONSIM supplies local business numbers across 650+ UK area codes, so if you need a different city or want to compare local number options across the country, we can help with that too.
Get a London number on your mobile
If you want a London business number without the hassle of a desk phone or app-heavy VoIP setup, ONSIM gives you a much simpler route.