Hi @dmarkovski, welcome to our forum!
The Xperia Z5 Compact supports VoLTE, but there are some other requirements that needs to be fulfilled as well for this to work.
- your operator and subscription (incl. SIM card) must support VoLTE for the device model you're using.
- depending on operator, your phone must sometimes be operator-branded and/or use operator-customised system software.
- your phone must be in range of an LTE/4G network.
For more information about availability with the operator you use, please get in touch with them to make sure that they support it for the device, your subscription supports it and if the device needs to have been bought directly from them.
I hope that answers your question!
