Compare
Compare ONSIM with other UK business phone providers
Honest, point-by-point comparisons of ONSIM against the main UK alternatives. ONSIM is a SIM-native landline provider - no app, no VoIP, no broadband dependency - so the right comparison depends on what you're actually weighing it against.
ONSIM vs bOnline
SIM-native landline (no app) vs cloud-VoIP phone system (app + desk phones). Best read if you're choosing between simplicity on mobile and a fuller PBX for a team.
Read the comparison →
ONSIM vs Vonage UK
Same shape of comparison as bOnline but framed for slightly bigger or more desk-based teams. Vonage is a full cloud PBX with IVRs, queues and CRM integrations.
Read the comparison →
ONSIM vs Virtual Landline Ltd
Two different UK companies with confusingly similar names. ONSIM (onsim.uk) and Virtual Landline Ltd (virtuallandline.co.uk) are both in the virtual-landline category but use different delivery models. Includes explicit disambiguation.
Read the comparison →
ONSIM vs Air Landline
One of our closest rivals - both deliver a landline number to your mobile without broadband. ONSIM starts at £5 with a SIM-native upgrade path; Air Landline is a well-reviewed £9.99 all-inclusive forwarding plan.
Read the comparison →
ONSIM vs Tamar Telecommunications
Both start at £5/mo for a virtual number. Tamar bundles rich forwarding features and upgrades you into VoIP; ONSIM upgrades you into a SIM-native landline with no app.
Read the comparison →
ONSIM vs SwitchboardFREE
SwitchboardFREE is a feature-heavy virtual-number platform (40+ free features, 95,000+ businesses). ONSIM is leaner but SIM-native - calls work like normal mobile calls.
Read the comparison →
ONSIM vs Yay.com
Yay.com is a polished UK cloud-VoIP phone system with apps and desk phones. ONSIM is the no-app, no-broadband alternative for mobile-first businesses.
Read the comparison →
ONSIM vs Ringover
Ringover is a cloud VoIP and contact-centre platform - AI transcription, power diallers, 100+ CRM integrations. ONSIM is the simple SIM-native landline. Opposite ends of the market, compared honestly.
Read the comparison →
ONSIM vs BT Digital Voice
A comparison of approaches, not like-for-like products: BT moves your landline onto broadband; ONSIM moves it onto the mobile network. What that means for power cuts, alarms and mobility.
Read the comparison →
Want the all-in-one view?
The head-to-head pages above are deep dives. For a side-by-side that includes bOnline, Vonage, Dialpad, Virtual Landline Ltd, Number People, AAISP and RingCentral on one screen, see our full provider table.
Frequently Asked Questions
Common questions about the ONSIM comparison pages.
How do I know which comparison is most relevant to me?
Pick the one closest to what you're actually considering. Weighing forwarding services? Start with Air Landline, Tamar Telecom, SwitchboardFREE or Virtual Landline Ltd. Weighing VoIP phone systems? See bOnline, Vonage UK, Yay.com or Ringover. Replacing a BT home phone? Read ONSIM vs BT Digital Voice.
Where can I see ONSIM compared to every UK provider at once?
The all-in-one comparison table lives at Best Virtual Landline Providers in the UK. It covers ONSIM, bOnline, Vonage, Dialpad, Virtual Landline Ltd, Number People, AAISP and RingCentral side-by-side at a glance. Use the head-to-head pages here for deeper dives.
Are these comparisons fair?
Yes - we try hard to be. Each comparison includes a 'When [competitor] is the better choice' section, links out to the competitor's own website, and avoids making claims about competitor pricing or features we can't verify live. If you spot something inaccurate, email support and we\'ll fix it.
Why does ONSIM compare differently to each of these?
Because they're different categories of product. bOnline and Vonage are cloud-VoIP phone systems (app + desk phones, broadband-dependent, rich call-routing features). Virtual Landline Ltd is in ONSIM's own category - UK virtual landlines for mobile-first businesses - and the comparison is closer. ONSIM's differentiator across all three is that calls run natively over the mobile network with no app and no VoIP.
Can ONSIM port my number in from any of these?
Yes. UK number portability is mandatory. ONSIM can port most UK landline numbers in - typically 10-14 working days from receipt of the porting form. Port-in is included on Landline SIM (one-off £20+VAT on Virtual Landline); port-out fee is £20+VAT. See the keep-your-landline-number guide for the process.
Skip the comparing - try ONSIM from £5/mo
7,500+ UK businesses already use ONSIM. Monthly rolling, cancel anytime. Live in minutes.