RCS vs. SMS: What's the difference?

When most people think of a typical text message, they're likely referring to Short Message Service, or SMS, a suite of protocols that has been a component of cellular networks for decades. With SMS, messages of up to 160 characters can be sent and received between devices residing on or across mobile communications networks.

In the last few years, however, a newer messaging format has emerged: Rich Communication Services (RCS). RCS is a revamped form of messaging that comes with a host of functionality and security features that SMS simply cannot provide. Let's examine RCS vs. SMS and discuss how they work and the technical requirements for each.

What is SMS and how does it work?

SMS does not use IP, nor does it require Wi-Fi or LTE/5G cellular access. Instead, SMS communications, on the other hand, are sent directly through the cellular network, like voice calls. That's why messages sent and received using SMS don't count against mobile carrier data plans.

By contrast, RCS and messaging platforms, such as WhatsApp and Facebook Messenger, are IP-based. These types of apps are known as over-the-top (OTT) platforms and use the mobile user's IP data plan to send and receive communications.

An upgrade to SMS, called Multimedia Messaging Service (MMS), accommodates the transmission of images, audio and video. MMS uses the same protocols and transport methods as SMS. In addition, MMS per-message payload caps are set much higher to accommodate the larger file sizes associated with multimedia content. MMS is beneficial in situations where cellular voice access is available but IP-based services are not.

What is RCS and how does it work?

RCS is the new kid on the block. Mobile carriers are shifting away from SMS and toward RCS to better compete with the popularity of OTT communications apps. The concept of RCS is simple: It provides the same feature-rich communications features -- among them group chat, delivery of high-resolution photos or videos, read receipts and location sharing -- found in the most popular IP-based communications services.

It's important to also note that RCS is an open standard, meaning that any device can incorporate the feature-rich service at no cost and with no concern over inoperability. Devices sending and receiving RCS messages must be connected to either Wi-Fi or LTE/5G IP data network service. Data sent and received counts against any mobile carrier data plans in place.

Compare RCS vs. SMS

The key difference between RCS and SMS is that SMS sends messages over the cellular network, while RCS content requires data connectivity before it can be transmitted. In some situations where data connectivity is not available, it's still possible to send and receive SMS-supported messages. With the expansion of LTE and 5G, however, internet connectivity is plentiful in most areas, enabling a feature-rich service.

As a result, RCS is considered by many to be a more convenient and wide-ranging communications platform than SMS and even other OTT counterparts, like WhatsApp, Facebook Messenger and Telegram. These third-party services require the sender and receiver to be logged in to and use the same app. RCS offers similar security functionality to third-party services, such as message encryption and verifying messages before they're delivered. SMS does not support these security features.

How to use RCS and what devices support it

RCS has been available through major U.S. carriers since 2019. Global carriers began offering RCS in 2022. Smartphones running Android OS 5.0 and higher can access RCS; users can enable or disable RCS chats via Settings > Chat features. From here, simply toggle the Enable chat features on to enable RCS.

Apple does not support RCS, and there is no indication it will do so in the near future. Instead, Apple continues to push its proprietary messaging system, iMessage.