If you divide your time between the UK and Spain, or have moved to Spain permanently, you do not necessarily need to make everybody use a Spanish mobile number. A UK telephone number can be delivered to a compatible VoIP phone through your internet connection in Spain.
Your callers still dial a UK number
Suppose you have a UKDDI UK telephone number connected to a SIP account. Friends or family in Britain call that UK number, UKDDI receives the call and sends it over the internet to the registered VoIP telephone in Spain.
From the caller's perspective, they are simply calling a UK number. Their own phone provider decides whether that call is included in their allowance or charged separately.
Your location does not determine where the phone rings
Traditional telephone numbers were historically associated with physical telephone exchanges and fixed lines. VoIP separates the telephone service from the physical line.
The receiving device might be a desktop VoIP phone in Alicante, a handset in a villa near Malaga, a softphone on a laptop in Barcelona or a business phone system with users in several countries.
Useful for people with homes in both countries
If you spend part of the year in Britain and part of the year in Spain, you can keep one familiar UK number rather than repeatedly telling people which international number to use.
Depending on the setup, you may take a configured VoIP telephone with you, register another compatible device or use a wider hosted phone arrangement.
A practical option for UK businesses with staff in Spain
The same principle can help UK businesses whose owners or employees spend time overseas. A customer can call the company's normal UK number while an authorised member of staff answers through a registered VoIP endpoint in Spain.
That can help the business keep its published UK contact number instead of exposing an employee's personal overseas mobile number.
Broadband quality matters
A VoIP phone does not need enormous bandwidth, but it does need a stable connection. Packet loss, latency, jitter and poor Wi-Fi can result in delayed speech, broken audio or dropped calls.
For a fixed home or office installation, connecting a desk phone directly to the router by Ethernet is normally preferable where possible.
What happens when I return to the UK?
Connect the SIP telephone to a suitable internet connection and allow it to register again. The UK number itself does not have to change just because the physical phone has moved.
That portability is one of the reasons SIP is useful for expats, second-home owners and international remote workers.
Choose your UK number and how you want to answer it
Search UKDDI number availability, then choose SIP trunk or hosted SIP-phone delivery. If you need a physical handset, compatible VoIP hardware can be added separately or alongside the service.
Service availability can depend on the local internet connection, firewall or router, local telecommunications rules and the UKDDI service configuration. Emergency calling should be handled according to the arrangements applicable where you are physically located.