Vodafone UK announced it has successfully tested VoLTE in the lab, but did not commit to a timeframe for commercial launch.

“Our trial of VoLTE, less than a year after the launch of our 4G network… is hugely important as we continue our work to build the UK’s best network,” said Fergal Kelly, Vodafone UK CTO.

The operator trumpets better voice and video calling quality, faster call set-up times – as well as simultaneous voice and data sessions over 4G – as some of the VoLTE benefits.

Carrying voice calls over 4G also frees up spectrum on 2G and 3G networks.

Vodafone said 4G coverage now reached 263 larger cities, towns and districts in the UK, as well as thousands of smaller communities.

EE, the largest mobile operator in the UK, previously said it would launch VoLTE in 2015.

There has been a flurry of VoLTE activity in the US and Asia in past weeks with AT&T, Bouygues Telecom, HKT, NTT Docomo, SingTel and T-Mobile US each declaring that they have either recently launched commercial VoLTE or are on the verge of doing so.

They join South Korea’s three major network operators, and Metro PCS (now part of T-Mobile US), which were first out of the VoLTE traps back in August 2012.