Can You Keep Your Phone Number When Switching to VoIP?
Yes. UK business phone numbers — including geographic 01/02 numbers, non-geographic 03 numbers, and most 08 numbers — can be ported to a VoIP system. AMVIA manages the porting process to ensure your existing numbers remain active throughout the migration.
Direct Answer
Yes — UK businesses can keep their existing phone numbers when switching to VoIP. Ofcom regulations give businesses the right to port geographic (01/02), non-geographic (03), and most 0800 numbers. The process takes 7–14 working days, during which your existing service remains live. AMVIA manages the complete porting process, including authorisation, cutover coordination, and DDI range mapping to the new VoIP platform.
What You Need to Know About Number Porting
These are the key aspects of the porting process that UK businesses should be aware of before switching.
What Numbers Can Be Ported
Most UK geographic (01/02), non-geographic (03), and freephone (0800) numbers can be ported. Some 0845 and 0870 numbers may have restrictions — AMVIA will confirm portability before starting the process.
How Long Porting Takes
A single number typically ports within 7–14 working days. Ranges (DDI blocks) or numbers on complex contracts may take longer. AMVIA provides a timeline at the outset.
Porting Authorisation
You'll need to provide proof of ownership of the number and authorise the losing provider to release it. AMVIA will guide you through the paperwork required.
Continuity During the Port
Your existing phone service remains active until the cutover is complete. AMVIA coordinates the timing to minimise any disruption to incoming calls.
DDI Ranges and Hunt Groups
If you have a range of DDI (Direct Dial In) numbers or complex call routing, AMVIA will map the existing configuration to the new VoIP platform before the port completes.
Adding New Numbers
In addition to porting existing numbers, VoIP makes it straightforward to add new numbers — local, national, or international — without additional physical lines.
Traditional ISDN/PSTN vs VoIP with Ported Numbers
How a VoIP system compares to a legacy phone system once your numbers are ported across.
| Feature | ISDN / PSTNTraditional phone lines | VoIP (Cloud Telephony)With ported numbersRecommended |
|---|---|---|
| Keep existing phone numbers | ||
| Add new numbers without new lines | ||
| Calls over your internet connection | ||
| Remote working supported natively | Limited | |
| Mobile app for desk number | ||
| No dependency on PSTN switch-off | At risk (2027 deadline) | |
| Typical monthly cost per user | £15–£35 line rental | £8–£20 |
BT Openreach's PSTN switch-off is scheduled for December 2027. All UK businesses will need to migrate to VoIP or an alternative by that date.
Frequently Asked Questions
Yes. UK businesses can port their existing geographic and non-geographic numbers to their new VoIP provider. Number porting requires a minimum lead time of 4-7 working days. Under the PSTN switch-off, phone numbers are not lost — they transfer through the porting process.
Yes, when paired with adequate connectivity. Modern VoIP systems on leased lines or FTTP deliver HD voice quality with latency under 9ms. 97% of UK workers say communication impacts their daily task efficiency. VoIP outperforms traditional telephony on features, cost, and flexibility.
Cloud-hosted VoIP typically costs £8-£25 per user per month depending on features. This includes calls, voicemail, mobile apps, and call recording. Most businesses save 40-60% compared to traditional PSTN costs. Microsoft Teams calling plans offer another option within the M365 ecosystem.
Direct Routing connects your Microsoft Teams environment to the PSTN via a certified Session Border Controller, enabling external calls from Teams. It provides more flexibility and often lower per-minute costs than Microsoft Calling Plans. It is ideal for businesses already using Microsoft 365.
VoIP transmits voice calls over your internet connection instead of traditional phone lines. It requires stable broadband or a leased line. Businesses typically save 40-60% on call costs compared to traditional telephony. Over 4.9 million UK businesses now use VoIP.
Switch to VoIP Without Losing Your Business Numbers
AMVIA manages the complete number porting process, from authorisation through to cutover. Speak to our team to understand the timeline for your specific numbers.
Related Questions
Business VoIP
AMVIA's cloud telephony service — fully managed VoIP for UK businesses with number porting included.
VoIP vs Traditional Landline
How VoIP compares to PSTN and ISDN on features, cost, and the implications of the 2027 switch-off.
Leased Lines
A leased line ensures consistent call quality after porting your numbers to VoIP.