You don’t literally “switch a single thread from SMS to RCS” on iPhone the way you might flip a chat from SMS to RCS on Android. Instead, you turn on RCS messaging system‑wide in Settings, and then new eligible conversations with Android users will use RCS automatically if your carrier and the other person support it.

How to switch from SMS to RCS on iPhone

1. Check that your iPhone can use RCS

For RCS to work at all, you need three things.

  • An iPhone running iOS 18 or later.
  • A SIM or eSIM with a carrier that supports RCS on iPhone.
  • Data connection (cellular or Wi‑Fi) when sending messages.

To check iOS version:

  1. Open Settings.
  2. Tap General → About.
  3. Look at Software Version (you want iOS 18 or later).

If you’re not on iOS 18 yet, go to Settings → General → Software Update and install the latest update.

To quickly sanity‑check carrier support:

  • In Settings → General → About , look at your Carrier line. Some guides mention seeing “Voice, SMS & RCS” near the carrier name when RCS is supported; if you don’t see anything about RCS at all, your carrier may not support it yet and RCS simply won’t turn on even if the toggle exists.

2. Turn on RCS Messaging in Settings

Once your phone and carrier qualify, enabling RCS is basically flipping one setting.

Step‑by‑step (iOS 18 and later):

  1. Open Settings.
  2. Scroll down and tap Apps.
  3. Tap Messages.
  4. Scroll to the Text Messaging or RCS Messaging section.
  5. Tap RCS Messaging.
  6. Turn the RCS Messaging toggle On.

On many iPhones this toggle is on by default after updating to iOS 18, but checking it makes sure you really have RCS enabled.

If you don’t see “RCS Messaging” at all, it usually means either:
– You don’t have a SIM/eSIM set up, or
– Your carrier doesn’t support RCS on iPhone yet, or
– You’re not actually on iOS 18+.

3. How to tell SMS vs RCS vs iMessage on iPhone

Apple keeps blue bubbles for iMessage and green bubbles for non‑iMessage chats, even when RCS is active.

  • Blue bubble = iMessage (Apple‑to‑Apple).
  • Green bubble (plain SMS/MMS) = older style SMS/MMS with no RCS features.
  • Green bubble (RCS) = RCS to Android or other non‑Apple devices, but with extra features like:
    • Read receipts.
    • Typing indicators.
    • Higher‑quality photos/videos.
    • Better group chat behavior.

So a green bubble doesn’t automatically mean “just SMS” anymore; it might be RCS behind the scenes, depending on the contact and both carriers.

4. “I switched a conversation to SMS – how do I switch it back to RCS?”

On iPhone, you don’t manually convert a specific existing thread from SMS to RCS the way you can on some Android messaging apps.

Instead, Apple’s Messages app decides per message:

  • If iMessage is available → use iMessage (blue bubble).
  • If not, and RCS is supported for both sides → use RCS.
  • If RCS is not available → fall back to SMS/MMS.

That’s why you see forum questions like “How do I switch SMS to RCS?” — the answer is always some version of “turn on the RCS toggle in Settings; you can’t force‑convert past SMS messages to RCS.”

Practical things you can try if one contact seems “stuck” on SMS:

  1. Confirm both sides have RCS enabled.
    • You: follow the steps above to turn on RCS Messaging.
    • Them (Android): make sure RCS/“Chat features” are enabled in Google Messages or their default messaging app and that their carrier supports RCS.
  1. Start a fresh thread.
    • Delete the old conversation with that contact and send a new message; some users report that new threads begin using RCS once the devices see each other as RCS‑capable.
  1. Send a new text instead of replying deep in the history.
    • On iOS betas, some people noticed a short delay before existing conversations started using RCS; sending a new message sometimes forced a capability check.
  1. Wait a bit.
    • Beta testers have reported it can take hours or days after enabling RCS before all eligible conversations flip over; in that time, Messages may still send plain SMS.

There is no supported way to “convert” old SMS messages into RCS chats: RCS only applies to new messages after both devices have RCS turned on.

5. Quick FAQ and mini‑forum vibes

“Is switching from SMS to RCS on iPhone worth it?”

  • If you text Android users often, RCS is a clear upgrade: better pictures, typing indicators, richer group chats, and more reliable media.
  • If you mostly text other iPhone users, you’re already getting those perks via iMessage, so RCS mostly matters only for the “green bubble” side of your life.

“Will RCS make green bubbles go away?”

  • No. Apple still keeps RCS chats as green bubbles; this is more about improving the experience for cross‑platform texting, not changing the bubble colors.

“Do I need a special app?”

  • No. On iPhone, RCS is built into the stock Messages app in iOS 18 and later; you just turn on the RCS Messaging option in Settings, and the app does the rest.

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