SIP trunk
Route calls into your existing PBX, 3CX, FreeSWITCH, Teams SBC or other SIP platform.
- Registration or IP routing details
- Starter, Regular and Plus concurrency tiers
- Fixed inbound and outbound call limits
UK BUSINESS NUMBERS · INSTANT ONLINE ORDERING
Your UK business number, connected your way
Choose a memorable UK number and connect it to your SIP trunk, a ready-to-use SIP phone, or your existing landline or mobile.
Reserved while you checkoutUK supportSecure card payment
YOUR NEW NUMBER020 3988 1234London
SIPYour PBX
IPSIP phone
↗Mobile divert
01 & 02 geographic03 UK-wide0800 freephoneNumber portingSIP-ready delivery
CHOOSE THE DELIVERY
One number. Three simple ways to answer.
Start with the service that fits today, then move to a different routing method as your business grows.
Hosted SIP phone
Get a hosted extension and select a compatible desk or cordless SIP phone during checkout.
- Ready for office or home working
- Professional outbound caller ID
- Optional preconfigured handset
Landline or mobile divert
Forward every call to a UK number you already use—no new equipment or app required.
- Fastest route to get started
- Change destination through support
- Ideal for sole traders and campaigns
LIVE INVENTORY
View all numbers →Featured numbers available now
029 2111 1111
Cardiff
from £2.50/month + VAT
028 8788 8888
Antrim
from £2.50/month + VAT
028 8688 8888
Antrim
from £2.50/month + VAT
028 7111 1111
Antrim
from £2.50/month + VAT
028 7022 2222
Antrim
from £2.50/month + VAT
028 4388 8888
Antrim
from £2.50/month + VAT
LOCAL PRESENCE
Popular UK area codes
Build a local presence with a geographic number while receiving calls wherever your team works.
Browse local numbersBUY WITH CONFIDENCE
View all buyer guides →
Answers to the questions businesses ask before ordering
Use a geographic number outside its area
A UK 01 or 02 number can be routed to a team outside the named area in permitted circumstances, but the area code retains geographic significance. The customer should deliberately request that area code, the call must retain the expected geographic tariff treatment, and marketing should not mislead callers about a physical office.
Read guide →SIP trunk vs hosted VoIP
Choose a SIP trunk when you already operate a compatible PBX or 3CX platform and want a provider connection for numbers and calls. Choose hosted VoIP when you want the phone platform, extensions and management delivered as a service. The right answer depends on who owns the platform, who supports it and how much control your business needs.
Read guide →01/02 vs 03 vs 0800 numbers
Use 01 or 02 when geographic identity matters, 03 when you want a UK-wide number charged to callers like a geographic call, and 0800 when you want the call to be free for the caller. The receiving business may still pay service and inbound-call charges.
Read guide →How UK number porting works
Number porting lets a customer keep an eligible telephone number when changing provider. The gaining provider submits the request using matching account and number details. Do not cancel the existing service before the port is accepted, and check whether broadband, alarms, payment terminals or other services depend on the old line.
Read guide →Make a business number ring a mobile
Yes. A UK business number can forward to a mobile, ring a mobile application through hosted VoIP, or use a phone system that rings desk and mobile devices. The best method depends on call volume, caller ID, voicemail, reporting, opening hours and the cost of forwarded calls.
Read guide →How many SIP channels do I need?
Size SIP capacity by simultaneous calls, not by the total number of employees. Count the highest expected inbound and outbound calls during the busiest period, include queued or transferred calls where the platform uses a channel, then add sensible headroom and monitor real usage after launch.
Read guide →UK-WIDE SALES NETWORK
Represent UKDDI in your local area
Introduce businesses to local phone numbers, SIP trunks, hosted VoIP, cloud voice and mobile-divert services, backed by the wider 39T agent programme.
LOCAL TERRITORIESUK-wide
Build relationships in an area you know, with recurring telecom services and technical support behind you.
READY TO CONNECT?
Find my UK numberChoose a number in minutes.
Your chosen number is held while you configure the service and complete payment.