https://www.theverge.com/2019/1/14/18181734/rcs-chat-google-fi-international-lte-speeds

Today, Google is announcing that it’s rolling out RCS Chat on the Google Fi network. Google is also announcing that it’s improving data speeds for users who roam.

The RCS rollout follows limited support on Verizon, Sprint, and T-Mobile. Google is making RCS available on a broader array of phones than Verizon and T-Mobile; it should work on Pixel phones, the Moto G6, LG V35, LG G7, and Android One Moto X. Other networks have launched RCS Chat on just a few phones, including the Pixel 3 on Verizon and some Samsung phones on T-Mobile.