SIP trunking

SIP trunking is a Voice over Internet Protocol (VoIP) service designed to make your colleagues easier to reach and your phone systems easier to run. SIP trunking from O2 can reduce your organisations costs by carrying voice traffic over a dedicated server.


O2 offers a fully managed service tailored to meet your organisation’s needs:

  • SIP trunking is a VoIP (Voice over Internet Protocol) service
  • You rent SIP trunks from us
  • We’ll provide a standard ethernet connection (with a managed router) connecting your Private Branch Exchange (PBX) estate into our SIP network
  • Your inbound and outbound calls can then be routed over our SIP network
  • Our SIP network connects with the traditional phone network


  • Installation and switch-over of numbers
  • Opportunities to reduce and consolidate the number of Internet Service Digital Network (ISDN) lines and to reduce PBX infrastructure
  • Calls across your internal network are free of charge
  • Only pay for what you need
  • Fully compatible with O2 Gateway to converge and simplify your communication requirements, delivering SIP trunking along with WAN, internet connectivity, Wifi, cloud and unified comms through a single connection at any location.


We can provide you with bespoke pricing specific to your organisation. For more pricing information on SIP Trunking please contact your Account Manager

How to buy