Until now Vodafone users had to use third party apps for calling over Wi-Fi.
Once this comes as standard it will mean those with poor connection indoors can still receive and make calls via their Wi-Fi connection.
Three currently offers an app for this purpose.
Vodafone will also be introducing VoLTE which allows users to make calls over 4G rather than the usual 2G or 3G connection.
VoLTE should mean the ability to have high definition phone calls that are much clearer than the current offering.
Of course this still depends on a stable 4G connection to offer a noticeably better quality of call.
VoLTE 4G calling can offer up to three times the bandwidth of 3G which should mean making video calls over the network will be a stable, clear possibility at last.
EE has also announced it will begin trailing VoLTE and Wi-Fi calling which will start with the Lumia 640 and 640 XL on its 7 April release and will work with the Samsung Galaxy S6 and S6 edge when they arrive.
Jeroen Hoencamp, Vodafone UK chief executive said, "Our Wi-Fi Calling service will ensure that our customers never miss a call.
It is another important step towards our commitment to build the UK’s strongest converged network."