Just after AT&T and Verizon announced their own VoLTE networks, T-Mobile has now announced theirs as well. An unlike Verizon’s, which won’t launch until later this year, T-Mobile is actually launching it in Seattle.
MetroPCS (which T-Mobile purchased in 2013), actually launched VoLTE in 2012, so T-Mobile is probably converting that network over to use. T-Mobile’s CTO Neville Ray says that VoLTE allows for “faster call setup times (almost twice as fast as a non-VoLTE call setup) and the ability to enjoy lightning fast LTE data speeds while on a call.”
There are devices that can already support it, too. Those include the LG G Flex, The Samsung Galaxy Note 3, and the Galaxy Light. T-Mobile says that their “engineering team is working tirelessly to launch VoLTE in additional cities and with more devices while continuing to build out T-Mobile’s Wideband LTE.” So if you don’t have a device that supports VoLTE right now, you will eventually.