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Award-winning SIP Trunks

Connect your PBX to the PSTN in minutes.

Prices from just £4 per channel, per month.




Why Gradwell?

Our own network

We operate and own our own network, so know everything there is to know about connectivity and trunking.

Trusted by thousands

Thousands of UK SMEs rely on us for secure and cost-effective SIP trunks every single day.

Resilient and secure

We are ISO certified and take our network security and resilience seriously.

What are SIP Trunks?

Designed to replace traditional phone lines, SIP Trunks use broadband internet connections to connect your business phone system to the traditional phone network.

Huge cost savings

Flexible and scalable

Resilient and secure

SIP Trunks


SIP Trunk Only
One channel included
From: ££4

per month

SIP Trunk International
One channel included
From: £POA

A range of international minutes


These prices are based on one channel. Talk to one of our consultants to get a bespoke price for your organisation.


All our SIP Trunk packages feature:

24/7 monitoring

99.99% uptime

Expert UK support

Trusted by

Bloom and Wild
Anytime Fitness

Our specialist SIP products

As well as our standard SIP Trunks, we also offer bespoke services for businesses around the UK.

High Volume

Dedicated SIP Trunks for call centres and high volume callers


Direct Routing

Use Microsoft Teams as your PBX with our SIP Trunks



Dedicated SIP Trunks designed to integrate with 3CX


Want to sell our SIP Trunks?

We offer a partner programme for a range of resellers.



How does high volume SIP differ from the normal SIP Trunks?
High-volume SIP Trunks run on a separate dedicated platform built for high volumes of traffic and CAPS. This allows you to use the volumes you want without any issues.
How long will porting my number take?
Porting numbers can take up to two weeks depending on how many you have! We will request it as soon as possible and inform you when your number has been ported.
How quickly can I scale up my SIP Trunk?  
Simply give our team a call on 01225 800800 and they will be able to get this sorted for you in minutes.
Is there a limit on how many phone numbers I can have? 
 Not at all! You can have as many as you like from as many locations as you want.
What makes Gradwell different?
Built in the UK, we have a team of over 20 developers who are constantly evolving and advancing our technologies. With a range of packages to suit your business needs, you can tailor our products and services to suit your business needs and demands.
Can Gradwell provide me an internet connection to run the SIP trunks over?
Gradwell has a wide range of connectivity options available that are suitable for running our SIP trunking services over. In just a few questions, our team will be able to advise which connectivity option is suitable for your business.

Get in touch with an expert today.