Sip Trunking Providers UK

Suitable for businesses who have VoIP server onsite and require minutes.
  • Calls to UK Landlines & Mobiles
    Calls to UK Landlines & Mobiles
  • Keep your existing number or choose a new UK number
    Keep your existing number or choose a new UK number
  • 1x Phone Line
    1x Phone Line
  • 1x UK Phone Number
    1x UK Phone Number
  • Online Control Panel
    Online Control Panel
  • Call Logs & Reports
    Call Logs & Reports
SIP 1000
  • Calls to UK Landlines & Mobiles
    1000 Minutes
  • Keep your existing number or choose a new UK number
  • 1x Phone Line
  • 1x UK Phone Number
  • Online Control Panel
  • Call Logs & Reports
SIP 3000
  • Calls to UK Landlines & Mobiles
    3000 Minutes
  • Keep your existing number or choose a new UK number
  • 1x Phone Line
  • 1x UK Phone Number
  • Online Control Panel
  • Call Logs & Reports
SIP 5000
  • Calls to UK Landlines & Mobiles
    5000 Minutes
  • Keep your existing number or choose a new UK number
  • 1x Phone Line
  • 1x UK Phone Number
  • Online Control Panel
  • Call Logs & Reports

Additional Phone Line

Phone Line


per month

Additional UK Numbers

01, 02, 03, 084, 087


per month

SIP Trunking Providers UK

As one of the premier SIP Trunking providers UK, 123pbx prides itself in offering reliable and efficient SIP Trunking solutions for businesses using VoIP technology. Our SIP Trunk UK services are created to enhance communication, reduce costs, and allow businesses of all sizes to go global seamlessly.


What is SIP Trunking?

SIP trunking is a technology designed to deliver and receive seamless voice and multimedia communications over the Internet. As opposed to Traditional ISDN telephone lines, SIP (Session Initiation Protocol) trunks allow voice and data services to converge onto a single line. SIP trunking uses an internet connection to make and receive calls instead of using traditional phone lines; therefore, it can be used with VoIP (Voice over Internet Protocol) technology. This results in increased scalability and reduced overheads, giving your business high-quality and cost-effective communication means.


How SIP Trunking Works with VoIP?

SIP trunking works by replacing the traditional PSTN (Public Switched Telephone Network) lines with SIP trunks so businesses can communicate over the Internet. It connects the VoIP phone system on your business site to the Internet Telephony Service Provider (ITSP) using SIP (Session Initiation Protocol).

Here is how a business can use VoIP SIP Trunking:

  • Integration with VoIP Systems:

Your business setting needs a high-speed broadband connection, which is necessary for VoIP technology. The SIP trunk is integrated with your onsite SIP-based VoIP PBX system. Once the integration is completed, the VoIP SIP Trunk system converges all your voice communications over the Internet.

  • Call Transmission:

Voice calls are transmitted over the Internet using the SIP protocol, which handles the initiation, management, and termination of the calls. This allows you to have clear and distortion-free communication.

  • Call Routing:

SIP trunks route your calls to the right destinations effectively, whether the recipients are other VoIP systems or traditional phone lines.


Increase Your Communications Agility with the Best SIP Trunking Providers


A business needs reliable communication to manage business operations smoothly, which is why choosing the right SIP Trunk Providers UK is necessary. 123pbx is one of the renowned SIP trunk Providers UK, providing top-tier SIP trunking services to simplify your business communication channels and make your business technologically competitive.


Benefits of SIP Trunk UK

SIP trunking provides several benefits compared to traditional phone lines, making it a highly preferred choice for businesses of every level.

  • Modern Phone System

Connect your VoIP phone system directly to the SIP trunk for unified communications with various advanced features. Whether you prefer an on-premise or cloud-based setup, the choice is yours.

  • Cost Savings

You can significantly reduce your monthly expenses for line rental and Direct Inward Dialing (DID) by eliminating physical phone lines and the associated hardware.

  • Easy Scalability

Adjust the number of SIP trunks as your communication needs evolve, ensuring both flexibility and costefficiency.

  • Uninterrupted Connectivity

Maintain continuous communication with an internet connection, providing a reliable backup solution in case of traditional landline failures.

  • Expanded Geographic Reach

Move office locations easily without changing phone numbers. There are no location constraints, allowing you to keep your original numbers.

  • Enhanced Customer Experience

Add regional and international numbers to your SIP relay, offering more options at a lower cost, thereby improving convenience for your customers.

Sip Trunking Providers UK

Why Choose Us As Your SIP Trunk Providers UK?



123pbx has established itself as one of the trusted SIP Trunk Providers UK for more than a decade. We constantly evolve with the SIP technology to give your businesses the highest quality service.


Bespoke SIP Trunk Solutions

Every business has varying communication requirements. That is why 123pbx offers customised SIP trunking services that align with your specific requirements. From a small start-up to a major enterprise, we offer SIP Trunk services for businesses of all sizes, catering for every demand for high-quality communication.


Competitive Pricing

Enjoy seamless business conversations at a very low cost throughout your VoIP calls! As the best sip trunk provider, 123pbx offers maximum value for your investment in our SIP Trunk services, guaranteeing you the best communication channel at an affordable price.


Security and Compliance

As a reliable sip trunk provider UK, 123pbx prioritises security, offering robust security measures to protect your communication from potential threats.


Seamless Integration

We seamlessly integrate SIP Trunks with your onsite communication infrastructure. Regardless of your business setting having a traditional PBX system or a modern VoIP technology, we offer a smooth transition with minimal disruption to your operations.


Nationwide Coverage

As leading SIP Trunk Providers UK, we offer nationwide coverage. No matter where your business is located in UK, we offer SIP Trunking in every part of the nation to address your communication needs.


Are You Ready To Level Up Your Communications Service?

If you are looking for smooth and cost-effective business communication systems, then it is time to switch to SIP Trunking Services by 123pbx. Contact us today to learn more about our SIP trunking services and how we can help you streamline your business communications, reduce costs and boost productivity.


Call Rates

International Rates

Country Description Code Rate Connection fee
Country Description Code Rate Connection fee

Let’s Get Started

Ready To Make a Real Change? Let’s Build this Thing Together!

All prices showing on the website are excluding VAT. We do not charge customers on time based dialing, which means you can call at any time of the day. Charges for 0845 and other premium or mobile operators may vary. Terms & Conditions apply.