Definition
RCS on iPhone is Apple's support for RCS messaging in the Messages app, introduced with iOS 18. iPhone users can exchange RCS chats, shown in green bubbles, with Android users when their carrier supports RCS on iPhone.
Apple's support documentation says that RCS on iPhone requires iOS 18 and a text-messaging plan from a carrier that supports RCS on iPhone. RCS messages appear in green bubbles, like SMS, but support features such as typing indicators, read receipts and high-quality media.
Apple documents end-to-end encrypted RCS (in beta, rolling out over time) from iOS 26.5, when all participants' carriers support encryption. Encrypted conversations show "Encrypted" with a lock icon. This follows the GSMA Universal Profile 3.0 work on MLS-based encryption.
For businesses, iPhone support widens the potential reach of RCS. However, RCS Business Messaging to iPhone users depends on carrier support and on which RBM features the iOS Messages app renders, so test rich cards, carousels and suggestions on iPhones in each target market.
Keep SMS fallback in place: in many markets, including several in the GCC, RCS availability on iPhone depends on operator rollout.