In short. On a recent phone, a message typed in the Messages app is almost never sent as an SMS: it travels over RCS (Android, via Google Messages) or iMessage (iPhone). Both protocols are tied to an account and transmit a profile, a "typing" indicator and read receipts. In other words, they make everything you were trying to hide worse.
Information verified on 10 November 2026 on the public pages of Arcep, the CNIL, service-public.fr and cybermalveillance.gouv.fr, as well as on the official documentation of Apple and Google. This article provides general information and is no substitute for the advice of a legal professional.
Why is my message no longer sent as an SMS?
Because your phone's Messages app picks the pipe itself. If both you and the recipient are compatible, it gives priority to RCS or iMessage, two internet-based messaging protocols, and falls back on classic SMS only when they fail. That switch is automatic, often invisible, and it changes everything where anonymity is concerned.
The SMS, as it has existed since the 1990s, is a very bare-bones message: a sender number, a recipient number, 160 characters and a network timestamp. It is precisely that bareness that makes it useful when you want to write without giving yourself away — and it is for the very same reason that the industry wanted to replace it.
RCS (Rich Communication Services) is the standard championed by the GSMA, rolled out in France mainly through the Google Messages app. iMessage is Apple's proprietary system, active as soon as two iPhones talk to each other. Both add high-definition photos, named group conversations, reactions, typing indicators and read receipts. And both rest on a persistent identity: an account, a device, an activation token.
What extra information does a recipient see with RCS or iMessage?
Far more than ten digits. Where an SMS shows nothing but a number, an RCS or iMessage message can carry a name, a profile picture, the information "read at 10:14 p.m." and the fact that you started typing and then gave up.
| Element visible to the recipient | Classic SMS | RCS (Google Messages) | iMessage |
|---|---|---|---|
| Sender number | Yes | Yes | Yes (or the account's email address) |
| Name and profile picture | No | Possible (RCS profile) | Possible (name and photo sharing) |
| "Typing…" | No | Yes | Yes |
| Read receipt | No | Yes, if enabled | Yes, if enabled |
| Bubble colour / label | — | RCS label | Blue bubble |
| Message editable or recallable | No | Varies | Yes, within a short window |
The blue iMessage bubble is a signal in itself: it tells the recipient that the message comes from an Apple device linked to an Apple ID. An RCS message is labelled as such in the app in the same way. If you were hoping to look like an unknown, unremarkable number, that label already tells part of the story.
Worse still: iMessage can hand over an email address as the sender when the message is sent from an account rather than from a SIM card. We have explained elsewhere what read receipts reveal about the sender; with RCS and iMessage, that mechanism is no longer an exotic option, it is the default setting in many configurations.
Do RCS or iMessage let you hide your number?
No, and that is by design. These protocols need to know who is talking to whom in order to route the message, display the conversation and sync receipts. There is no RCS or iMessage equivalent of the #31# prefix, and there never will be: the sender's identity is part of the format.
It is worth recalling in passing that #31# does not work for an ordinary text message either — the subject is covered in detail in our article on the #31# prefix and SMS. The difference is that a classic SMS at least remains a message without a profile: only the number travels. With RCS and iMessage, you add a layer of account, device and behavioural metadata.
Three common misconceptions deserve to be cleared up:
- "I turn off my name, so I'm anonymous." No: hiding name and photo sharing removes one line of display, not the link between the message and your number or your account ID.
- "It's encrypted, so it's anonymous." Encryption protects the content, not the identity. The CNIL regularly points this out with regard to metadata: who, when, how many times, from which device. That is the heart of the matter in our feature on what metadata reveals.
- "I'm on Wi-Fi, so my number isn't sent." The network you use changes nothing: your RCS or iMessage account is already registered with your number.
How do you go back to classic SMS on Android?
By turning off RCS features in Google Messages. The message then goes out as an SMS or MMS, with the limits of the format: 160 characters per segment, no profile, no native read receipt.
The exact path, in Google Messages (November 2026 version):
- Open Google Messages.
- Tap your profile picture at the top right, then Messages settings.
- Go into RCS chats (sometimes called "RCS features").
- Turn off the Turn on RCS chats switch.
- Go back, then check in the conversation that the RCS label has disappeared from the input field.
Depending on the manufacturer, the stock Messages app (Samsung Messages, for instance) has its own "RCS chats" setting under Settings → More settings. And if you do not use Google Messages, check both apps: sometimes only one of them gets disabled.
Two useful remarks. First, deactivation is not always instant: deregistering from the service can take a few minutes, and messages already queued will go out under the old setting. Second, a phone with full storage or a very low battery may delay sending and give the impression that the setting has not taken effect — we cover those cases in the article devoted to SMS sending failures.
If you really want to keep your uses separate, the cleanest approach is not to mix accounts on a single device. A basic mobile phone, of the push-button type knows nothing of RCS or iMessage: it sends SMS only, with no profile, no syncing and no account. For occasional use, it is often the most transparent solution.
How do you turn off iMessage on an iPhone?
From Settings, by switching off iMessage and allowing sending as SMS. Be careful: turning off iMessage also changes how you receive messages, so do it knowingly.
In iOS 26 (path verified in November 2026):
- Open Settings → Apps → Messages.
- Turn off iMessage.
- Turn on Send as SMS so that messages switch over to the mobile network.
- Under Share Name and Photo, turn off sharing.
- Turn off Read Receipts if you have not already done so.
One technical point often overlooked: if you turn off iMessage without deregistering your number, other iPhones may keep sending you blue messages that never arrive. Apple offers a dedicated page for deregistering a number from iMessage; that is the step to take before giving away or reselling an iPhone, as we point out in our guide to the phone that had a life before you.
For anyone who regularly swaps a SIM card between two devices, a small SIM ejector tool and a SIM card holder will stop you losing the tray or scratching it. They are unremarkable accessories, but they make all the difference when you juggle several numbers.
Are RCS and iMessage a problem for the sender or for the recipient?
For both, but not in the same way. On the sender's side, these protocols add identity. On the recipient's side, they add context: an RCS or iMessage message is harder to pass off as something sent from an anonymous gateway, and it leaves a richer trace on the phone.
If you receive a message and are trying to work out where it comes from, the protocol is already a clue. A message shown as an SMS with an alphanumeric sender (a string of letters instead of a number) almost always comes from a professional gateway. An RCS message or a blue bubble, by contrast, implies an active account behind it. It is one of the first reading reflexes described in our article on identifying the sender of an anonymous SMS.
One limit holds true in every case: neither you nor the recipient can trace a number back to a subscriber. Only a judicial authority can obtain that information from the operator, within the framework laid down by the French postal and electronic communications code. If the message you received amounts to harassment or a threat, the route to take is filing a complaint, and you must keep usable evidence: the method is set out in detail in our guide to using an SMS as evidence in court. To archive screenshots off the phone, an encrypted USB stick remains safer than emailing them to yourself.
Which method should you choose, depending on what you actually want?
It all depends on the level of discretion you are after and on whether or not you need a reply.
| Need | Suitable solution | What remains visible |
|---|---|---|
| Write without my number showing | Online sending gateway | A short code or an alphanumeric sender |
| Write and receive a reply | Dedicated secondary number | The secondary number, not the main one |
| Write once, with no follow-up | Gateway, complete self-contained message | Service sender |
| Keep work and personal life apart | Dual SIM or eSIM | Two separate numbers, both identifiable |
For sending without disclosing your number, the procedure is described on our page send an SMS without giving your number. If you need a reply, the page receiving a reply explains why a return channel always implies an identifier somewhere — and how to limit what it reveals. Finally, the choice between a gateway and a disposable number is compared in anonymous SMS or disposable number.
In practice, the most durable solution for anyone who regularly writes to strangers without wanting to hand over their personal number remains the secondary number, via dual SIM or eSIM. We covered it in the article on dual SIM as a secondary number. With that kind of setup, remember to check that RCS and iMessage are not active on the secondary line: the setting is sometimes applied per line, sometimes globally, depending on the device.
Points to watch out for
- Check before writing, not after. Open the conversation and look at the input field: "SMS", "RCS" or "iMessage" is usually indicated there. It is the only reliable check.
- Cloud backup. iMessage and RCS can sync conversations across several devices and archive them. A message deleted from the phone may survive elsewhere.
- The setting can come back. A system update or a reinstall of the app can re-enable the enriched features. Check after every major update.
- Battery and coverage. An RCS message that fails sometimes falls back automatically to SMS, and vice versa. That silent switch changes what the recipient sees. A compact portable charger at least keeps the battery out of the equation.
- The recipient's lock screen. Whatever the protocol, the notification may display a preview of the text in front of any onlooker: that is the subject of our article on what the lock screen reveals.
And what about the law in all this?
The protocol changes nothing about the legal framework. Writing to someone without revealing your number is not illegal in France; what is punishable is the content and the behaviour — harassment, threats, identity theft, blackmail. The applicable provisions are found in the French criminal code and are set out on service-public.fr; we went over them in the article on the legality of anonymous SMS in France.
Conversely, do not count on RCS or iMessage to shield you from an investigation: an account means a customer file, an activation history and IP addresses. A classic SMS, for its part, leaves a trace with the operator. In both cases, anonymity towards the recipient and anonymity towards the judicial authorities are two different things. To dig deeper into that distinction, see our analysis of how traceable an anonymous SMS really is. And if anonymity is a subject you want to get to grips with, the shelf of books on digital privacy offers serious reading, more useful than a pile of tips and tricks.
Frequently asked questions
Can you send an RCS message with a withheld number? No. RCS offers no number-withholding function: the sender's identity is part of the protocol, which relies on an account linked to your mobile line.
Does turning off RCS make my texts anonymous? No. It removes the profile, the read receipts and the typing indicator, but your number is still displayed. To write without showing your number, you need a gateway or a secondary number.
How can I tell whether my message went out as an SMS or as RCS? Look at the conversation's input field: the app indicates "SMS", "RCS" or "iMessage" there. On an iPhone, the bubble colour is also an indicator (blue for iMessage, green for SMS).
Should you deregister your number from iMessage when you change phones? Yes, it is strongly recommended. Otherwise, messages sent from iPhones will keep going to iMessage and will never reach your new device.
Is RCS encrypted? RCS conversations via Google Messages are end-to-end encrypted in certain configurations, but encryption protects the content, not the sender's identity or the conversation's metadata.
Updated on 10 November 2026. The settings paths mentioned correspond to Google Messages and iOS 26 as of that date; they may change with updates.
