There is nothing to add to a plan and nothing to buy. RCS runs over Wi-Fi or mobile data rather than the cellular text channel, so it draws on data rather than a texting allowance.
Which app carries T-Mobile RCS messaging
On Android, Google Messages, talking to the Jibe backend that Google operates for most carriers. On iPhone, Apple's own Messages app, which added RCS in iOS 18.1 in October 2024 and needs the carrier to have switched it on, which T-Mobile has.
T-Mobile got there first among the US networks, but the destination is the same one the others arrived at: a single Google-backed client on Android rather than a carrier-specific app. If a T-Mobile handset is running a manufacturer messaging app and chat features look missing, that is usually the whole explanation. See does Samsung support RCS.
Turning it on
On Android: Google Messages, profile menu, Messages settings, RCS chats, on. On iPhone: Settings, Apps, Messages, RCS Messaging. The phone then registers with the network, which usually takes seconds and occasionally longer. How to turn RCS on and off has both walkthroughs.
If RCS is not working on T-Mobile
- Stuck on "Setting up". Registration wants mobile data at least once; Wi-Fi alone often will not finish it. RCS waiting for activation has the rest.
- Rich in some threads, plain in others. Expected. RCS upgrades a conversation only when both ends support it, and falls back to SMS otherwise.
- Missing on a prepaid line. Metro by T-Mobile and the other sub-brands do carry RCS, so this is usually the default-app or the registration, not the plan.
- Gone after a SIM swap or eSIM transfer. Registration is bound to the line and has to redo the handshake.
See why RCS is not working for the full order of checks.
What T-Mobile support means if you send business messages
One thing is specific to T-Mobile and worth knowing before you budget, because it is the only US carrier that charges it: a one-time $500 sender activation fee per RCS sender, and $500 again for a short-code setup or migration. It is a carrier charge rather than a platform one, and SimplyRCS passes it through at cost on its own line rather than absorbing it into a rate. Every figure is itemised on the pricing page.
Beyond that fee, nothing about sending to T-Mobile is different. A verified sender renders on a T-Mobile handset exactly as on AT&T or Verizon, the same RBM agent approval covers all four networks, and there is no T-Mobile-specific registration on top of it.
T-Mobile's row, next to the other three national carriers and their prepaid brands, is kept current in the RCS carrier support tracker.
- T-Mobile was the first US carrier to launch RCS.
- RCS via Google Messages (Android) and Apple Messages (iPhone, iOS 18.1 and later); encrypted RCS supported from iOS 26.5.
- Metro by T-Mobile and the other prepaid sub-brands also carry RCS.
- T-Mobile is the only US carrier charging a one-time sender activation fee, $500 per RCS sender, passed through at cost.
- RCS on T-Mobile uses data rather than the SMS channel, so it does not draw on a texting allowance.