Quick Answer
To hide your caller ID for an individual call in South Africa, dial #31# followed immediately by the phone number you wish to call (for example, #31#0821234567) and press the call button. This prefix suppresses your Caller Line Identity (CLI) for that single call without altering your permanent device settings.
- Per-Call Private Code:
#31#+ Destination Number - Check Status Code (MMI/GSM):
*#31# - Permanent Device Setting: Phone App > Settings > Supplementary Services / Call Settings > Show Caller ID > Hide Number
- Network Availability: Vodacom, MTN, Telkom, and Cell C (subject to SIM type and contract provisioning).
- Last Verified: July 2026
What the Service Is and Who Can Use It
Caller Line Identity Restriction (CLIR) is a mobile network and handset capability that prevents your phone number from displaying on the recipient’s screen when you place an outgoing call. In South Africa, this feature is available across major cellular providers, including Vodacom, MTN, Telkom Mobile, and Cell C.
Eligibility and Network Scope
- Prepaid Users: Generally enabled by default for per-call hiding using dial codes (
#31#). - Contract/Postpaid Users: Network-level restriction (CLIR) may require activation via customer service (e.g., calling 135 on MTN) or via provider self-service portals.
- Exclusions: Emergency services (such as 10111, 112, or 10177) and certain toll-free numbers bypass caller ID restriction; your number will always be visible to emergency dispatchers regardless of your settings.
How Private Number Settings Work
Before You Start
- Identify standard prefixes versus MMI/USSD codes: Calling codes like
#31#are standard GSM dial prefixes sent directly with the call string, not interactive USSD session menus. - Verify Dual-SIM selection: If using a dual-SIM phone, ensure you dial from the specific SIM card configured for the desired network rules.
Verified Step-by-Step Process
Option A: Per-Call Hiding (Temporary)
- Open your device’s Phone / Dialer application.
- Enter
#31#. - Enter the full 10-digit South African mobile or landline number immediately after the code (e.g.,
#31#0831234567). - Press Call. The call will connect with your number displayed as “Private,” “Withheld,” or “Anonymous”.
Option B: Device-Wide Hiding (Permanent until changed)
- Android: Open Phone App > Tap Three Dots (Menu) > Settings > Supplementary Services / Calling Accounts > Caller ID > Select Hide Number.
- iOS (iPhone): Open Settings > Phone > Show My Caller ID > Toggle to OFF.
Confirmation or Expected Result
When properly applied, the call recipient’s device will display Private Number, Withheld, or Unknown instead of your 10-digit phone number.
Note: If the call fails to connect or gives an error like “Service not allowed” or “Check network services,”your network provider has restricted CLIR on your SIM card. You will need to contact your network provider or activate it via their official portal.
Fees, Limits, Eligibility, and Processing Times
| Feature / Detail | Specification | Notes |
| Prefix Charge | Free | Dialing #31# does not incur extra charges beyond standard call rates. |
| Call Billing | Standard Airtime / Minute Bundles | Standard call rates apply to the call duration. |
| Processing Time | Instant | Takes effect immediately on the initiated call. |
| Daily Limits | None | Can be used on individual calls as needed. |
| Network Restrictions | Account Dependent | Postpaid accounts may require explicit CLIR activation via customer care. |
Common Problems and Troubleshooting
Code, Session, SIM, or Account Errors
- “MMI Code Invalid” or Call Fails Immediately: Ensure you dial
#31#directly before the destination number without spaces or symbols. Do not attempt to run#31#as a standalone USSD menu query unless checking status with*#31#. - Recipient Still Sees the Number: If using WhatsApp Calling, VoIP apps, or calling emergency numbers, network-level CLI blocking codes do not apply. Use the specific application settings or standard cellular network calls.
- Dual-SIM Misconfiguration: On dual-SIM handsets, verify that the primary outbound voice SIM supports CLIR or that the correct SIM was selected when tapping the call button.
When the Service Has Changed or Is Unavailable
If your network blocks caller ID suppression, you cannot override it using dialing codes. You must request Caller Line Identity Restriction (CLIR) activation directly through customer support or your subscriber portal.
Official Alternatives
When network prefixes fail or are blocked by operator policy, use these verified methods:
- Device Operating System Settings: Adjusting your iOS or Android caller ID settings directly alters outgoing call headers without relying on network codes.
- Operator Apps and Web Portals:
- Vodacom: Log into My Vodacom > Services > Caller Identity (CLIP/CLIR).
- MTN: Dial
135or use the MTN App to check caller identity management settings. - Telkom Mobile: Manage voice account features via the Telkom Mobile App or online portal.
- Customer Support: Contact your network provider’s support desk to verify if CLIR (Caller Line Identity Restriction) is provisioned on your account.
Safety and Privacy
- Avoid Unverified Third-Party Apps: Never download untrusted third-party “number hider” apps that demand full call log access or access to sensitive permissions.
- Legal and Fair Usage: Hiding your caller ID does not grant legal immunity. Authorities and telecommunication operators can trace calls under lawful interception protocols in cases of harassment or illegal activity.
- Call Rejection Warnings: Many users enable automatic call blocking for anonymous or private numbers. Using a private number may cause your call to be declined automatically.
Related Network Guides & Resources
- Mobile Network USSD Codes — Full directory of mobile service shortcodes in South Africa.
- USSD Code For Private Number MTN — Specific guide for MTN contract and prepaid caller ID configuration.
- Call Barring USSD Code — Manage incoming and outgoing call restrictions on your handset.
- Call Forwarding USSD Code — Learn how to set up call diverts and manage unanswered calls.
- USSD Code To Convert Airtime To Voucher — Airtime management and conversion guides.
- MTN Services Guide — Account management, balance checks, and network tools.
Frequently Asked Questions
What is the current USSD Code For Private Number?
To hide your caller ID on a per-call basis in South Africa, prefix the phone number with #31# (e.g., #31#0821234567). To check status, dial *#31#.
Can caller ID be hidden for one call only?
Yes. Using the #31# prefix before a recipient’s number hides your caller ID solely for that individual call. Subsequent calls made without the prefix will display your standard mobile number.
Does the setting work on every network?
While #31# is a global GSM standard supported by South African operators, some contract/postpaid lines require CLIR to be explicitly enabled on the account by customer support before prefix codes will function.
How can caller ID be shown again?
If you changed your device settings to hide your number for all calls, navigate to your phone dialer’s Settings > Supplementary Services / Phone > Show Caller ID and select Show Number or Network Default.
What should I do if the mobile caller ID USSD route does not work?
Change your caller ID visibility directly inside your phone handset settings, or contact your network provider’s call center (e.g., 135) to verify that Caller Line Identity Restriction (CLIR) is active on your account.
