Last checked: 26 June 2026
Quick Support Route
If you need to MTN replace SIM, the safest route is to start with MTN’s official SIM swap process, because you are trying to move your existing MTN number onto a new SIM card. This is usually needed when your MTN SIM is lost, stolen, damaged, blocked, or no longer works in your phone.
Quick answer: MTN currently says prepaid users should buy and activate a new SIM, then dial *135*3# from the new SIM to start the SIM swap process. MTN’s USSD support page also lists *126*7927# as a SIM-swap-related code, so check the latest MTN menu before publishing or relying on one code only. (MTN)
| Situation | Best next step |
|---|---|
| Your MTN SIM is lost or stolen | Secure the number first, then replace the SIM |
| You bought a new MTN SIM | RICA and activate it before starting the swap |
| You want to keep your old MTN number | Use the SIM swap route, not a new-number activation |
| The USSD code does not work | Contact MTN or visit an MTN store |
| You suspect SIM swap fraud | Stop and contact MTN fraud support immediately |
Do not continue with a SIM swap if someone is asking you for an OTP, banking PIN, app PIN, card PIN, email password, or WhatsApp verification code. A real SIM replacement may require identity and account checks, but you should only complete them through MTN’s official channels.
For the broader network guide, read how to do SIM swap South Africa. If your phone suddenly lost signal and you did not request a SIM swap, read SIM swap fraud South Africa before trying again.
What You Need Before You Start
Before starting an MTN SIM replacement, prepare the information MTN may use to confirm that you are the legitimate user of the number.
You may need:
- A new MTN SIM card.
- The MTN number you want to keep.
- Your South African ID, ID card, passport, or accepted identity document.
- Proof of residence if RICA verification is required.
- Access to the new SIM and a working phone.
- Answers to MTN security questions about the number.
- A safe contact route if the old SIM is lost, stolen, or no longer receiving SMSs.
MTN’s PayAsYouGo terms state that a user must be RICA-compliant to conduct a SIM swap and that MTN may require security questions to confirm the legitimate user of the cellphone number. MTN also states that RICA activation requires an ID book, ID card, or passport plus proof of residence not older than three months. (MTN)
Check network/account status
Do a few safe checks before assuming you need to replace the SIM.
Check whether:
- The SIM is inserted correctly.
- The phone is not on airplane mode.
- The phone has MTN signal in your area.
- Restarting the phone restores service.
- The SIM is asking for a PUK rather than needing replacement.
- The number has been inactive for too long.
- The account is suspended, blocked, or under verification.
- You are using the new SIM before starting the swap.
A SIM replacement is not always the answer. If the issue is only a blocked SIM PIN or PUK problem, use the PUK support route instead of starting a SIM swap.
Retry safely
Only retry the MTN SIM swap through an official MTN route. Do not follow a code or link sent by an unknown person claiming to “help” you replace your SIM.
A safe retry flow is:
- Buy a new MTN SIM.
- RICA and activate the new SIM.
- Insert the new SIM into your phone.
- Dial the current MTN SIM swap code or open the official MTN self-service menu.
- Follow the prompts carefully.
- Complete the security checks.
- Wait for MTN’s confirmation.
- Restart your phone once the swap is complete.
MTN’s terms say a SIM swap lets a user keep their old MTN cellphone number if it is still active, available on MTN’s network, not recycled, and not already in use by another customer according to MTN’s systems. The terms also state that only one cellphone number can be swapped at a time and that the new number must not have been active or used to make calls for more than 24 hours under those SIM-swap conditions. (MTN)
Provider-by-Provider Options
This page is only for MTN. Do not use Vodacom, Telkom, Cell C, or bank USSD codes to replace an MTN SIM.
| Provider or task | Use this route |
|---|---|
| MTN replace SIM | Use MTN’s official SIM swap code, self-service menu, customer care, MTN Chat, or an MTN store |
| MTN lost SIM | Start with block lost SIM South Africa if the phone or SIM was lost or stolen |
| MTN SIM swap code | Verify the latest MTN code before use because USSD menus can change |
| MTN account help | Use MTN USSD codes for balance, recharge, PUK, and self-service codes |
| SIM swap fraud | Use SIM swap fraud South Africa if you did not request the swap |
Official support route
Use official MTN support if the USSD code fails, your new SIM does not activate, you cannot answer the security questions, or your number does not move to the new SIM after the expected process.
MTN’s customer service charter lists 135 as its call-centre number from a cellphone and says calls from an MTN number are free. The same charter also lists Facebook, Twitter, and [email protected] as support contact options. (MTN)
If you are calling from a non-MTN phone, MTN’s contact page lists 083 135. For suspected fraud, MTN’s support pages list [email protected] and a fraud helpline route. (MTN)
When You Must Contact Customer Care
Contact MTN directly instead of repeatedly trying the code if the replacement involves identity, ownership, fraud, or a failed SIM swap.
You should contact MTN when:
- Your MTN SIM or phone was stolen.
- Your MTN number is linked to banking, WhatsApp, email, business accounts, or OTPs.
- You received a SIM swap message you did not request.
- Your phone suddenly lost signal for no clear reason.
- Someone asked you for an OTP to stop or approve a SIM swap.
- The new SIM is active but the swap does not complete.
- You failed the security questions.
- Your old number may have been recycled or suspended.
- You are a contract customer and the account holder details need to be checked.
- You need in-store RICA or identity verification.
If your device or SIM is lost or stolen, MTN’s terms state that you must report the loss or theft to the South African Police Service and request MTN to suspend the SIM card. (MTN)
Escalation route
Treat a suspicious or unauthorised SIM swap as urgent.
Take these steps:
- Contact MTN fraud support immediately.
- Contact your bank and ask them to secure your banking profile.
- Change passwords for email, banking, WhatsApp, and important online accounts.
- Do not share OTPs with anyone.
- Save screenshots of suspicious SMSs, emails, calls, and WhatsApp messages.
- Ask MTN for a reference number.
- Visit an MTN store if identity verification is needed.
For the full safety path, use SIM swap fraud South Africa. If the SIM was lost with your phone, use block lost SIM South Africa before replacing the SIM.
Related SIM, PUK, and Account Guides
Use these related guides for the next step:
- How to do SIM swap South Africa — for the broader SIM swap process across South African networks.
- SIM swap fraud South Africa — for suspicious SIM swap messages, sudden loss of signal, OTP risk, and account takeover concerns.
- MTN USSD codes — for MTN balances, recharge, PUK, customer care, and other MTN self-service codes.
- Block lost SIM South Africa — for lost or stolen SIMs before replacement.
FAQs
What is MTN replace SIM used for?
MTN replace SIM is used when you want to keep your existing MTN number but move it onto a new SIM card. This may be necessary if your SIM is lost, stolen, damaged, blocked, or no longer works properly.
What is the code for MTN replace SIM?
MTN currently says users can buy and activate a new SIM, then dial *135*3# from the new SIM to start the SIM swap process. MTN’s USSD support page also lists *126*7927# for swapping an old SIM card for a new SIM card. Because USSD menus can change, verify the latest route with MTN before publishing or using it. (MTN)
Does this USSD code need airtime or data?
USSD usually works through a mobile network menu rather than mobile data, but the SIM must still be active enough to access MTN’s menu. If the code does not open, check signal, restart the phone, confirm that the new SIM is active, and contact MTN if it still fails.
What should I do if the code does not work?
Stop retrying if the code keeps failing. Check that the new SIM is inserted correctly, active, RICA-compliant, and connected to the MTN network. If the issue continues, contact MTN customer care, use MTN Chat, or visit an MTN store.
Are there costs, limits, or eligibility rules for MTN replace SIM?
Do not assume a fee, limit, or approval rule unless MTN confirms it. MTN’s public terms confirm that SIM swaps require RICA compliance, security checks, and an available old MTN number. MTN’s terms also say lost or stolen SIM cards must be replaced at the user’s own cost, but current store pricing should be checked directly with MTN. (MTN)
What should I do if my MTN SIM was stolen?
Secure the number first. Contact MTN, report the stolen phone or SIM, speak to your bank if the number receives banking OTPs, and then continue with the SIM replacement. Use block lost SIM South Africa for the safety checklist.
When should I read the SIM swap fraud guide?
Read SIM swap fraud South Africa if your phone suddenly loses signal, you receive a SIM swap message you did not request, your banking app behaves strangely, or someone asks for an OTP connected to your number.
Where can I find related MTN USSD codes?
Use MTN USSD codes for related MTN self-service codes, including balance checks, recharge help, PUK support, customer care, and other account menus.