SIM Swap Fraud: How to Protect Your Bank and Crypto

Your phone number does a lot more work than you might think. It receives your bank alerts and one-time passwords (OTPs). It lets you reset forgotten passwords. It's tied to USSD banking, mobile money and many of the apps where you keep your crypto. For a fraudster, your number is a master key.

SIM swap fraud is how criminals steal that key. The good news is that a few simple habits make you a much harder target. Here's how the fraud works, the warning signs, and what to do if it ever happens to you.

What is SIM swap fraud?

In a SIM swap, a fraudster convinces a mobile network, or someone working at a retail point, to issue a new SIM card for your number. They usually pretend to be you and claim your SIM was lost, stolen or damaged.

Once the new SIM is active, your own SIM goes dead. Calls and text messages meant for you, including bank OTPs and password reset codes, now go to the fraudster's phone. They don't need your handset at all.

How the fraud usually unfolds

Most SIM swap attacks follow a similar pattern:

1. Gathering your details. The fraudster collects personal information: your full name, date of birth, phone number, NIN, BVN, account details, or the email linked to your bank. This can come from phishing calls, fake "account update" messages, data you've posted on social media, or leaked databases.
2. Requesting the swap. Armed with your details, they request a replacement SIM for your number.
3. Your line goes quiet. Your phone shows no signal or says the SIM isn't recognised. Fraudsters often time this for late at night, weekends or public holidays, when you're less likely to notice or get quick help.
4. Taking over your accounts. With your number in hand, they reset passwords, request OTPs, and try to move money out of your bank, mobile wallets and crypto apps as quickly as possible.

Warning signs to watch for

Act fast if you notice any of these:

• Sudden loss of signal. Your phone shows "No service", "SIM not provisioned" or "Emergency calls only", while people around you on the same network have signal.
• Unexpected "SIM changed" messages. A text saying your SIM has been replaced or a swap has been requested, when you asked for nothing.
• Calls and texts stop arriving. Friends say they've called but your phone never rang.
• Login or reset alerts you didn't trigger. Emails about password changes, new device logins or new withdrawal addresses.
• Strange calls asking you to "confirm" a code. Someone claiming to be from your bank or network asking you to read out a code you just received. This is often the moment before a takeover.

How to protect yourself

Use an authenticator app instead of SMS codes where possible

Many apps let you choose how you receive login and withdrawal codes. Where you're offered an authenticator app, use it. The codes are generated on your phone itself, so moving your number to a new SIM doesn't give them away. Keep SMS as a backup only if there's no other option.

Keep your SIM and NIN details private

Your NIN, BVN, date of birth and phone number are the raw materials for a SIM swap. Don't post them online, don't send photos of your ID card on chat apps unless you truly must, and be suspicious of anyone who calls asking you to "verify" these details. Your bank and your network won't call you to collect them.

Set a SIM PIN and strong app PINs

Most phones let you lock your SIM card with a PIN in the security settings. This protects you if your phone is stolen, because the SIM can't be used in another handset without it. Change the default PIN to one only you know.

Use different, strong PINs for your phone lock screen, banking apps and crypto apps. Avoid your birth year, 1234 or repeated digits.

Never share OTPs, with anyone

An OTP is a key, not a formality. No genuine bank, network or crypto platform will ask you to read one out. KWIQ will never ask for your password, PIN or one-time codes.

Add a second line of defence

• Turn on email alerts for logins and transactions, so you still hear about activity if your SIM goes dead.
• Secure the email account itself with a strong password and an authenticator app, because it's often the way to reset everything else.
• Consider a separate number for money. Some people keep one line just for banking and crypto apps and never share it publicly.

For a wider look at staying safe, read our guide on the importance of cybersecurity for crypto users.

What to do if you think your SIM has been swapped

Speed matters most here. Every minute counts.

1. Call your network immediately from another phone. The harmonised customer care number on every Nigerian network is 300. Ask them to block the line and stop any SIM replacement.
2. Call your bank and ask them to freeze your accounts and cards until you've regained control.
3. Contact your crypto and payment apps. For KWIQ, reach our 24/7 support through live chat in the app or on kwiq.app, by email at admin@kwiq.app, or by phone on +2348098460000.
4. Change your passwords from a device and email account the fraudster can't access.
5. Visit your network's office with your ID to get your number back on a SIM you control.
6. Keep a record and report it. Write down the time you lost signal and screenshot any odd messages. Report the fraud to the police and share the details with your bank.

Small habits, big protection

You don't need to become a security expert. Lock your SIM, guard your personal details, use an authenticator app where you can, and treat sudden "No service" as a red flag rather than a network glitch. It's also worth learning the common tricks scammers use, from P2P scams to fake crypto schemes.

Keep your money moving safely

KWIQ has served over 100,000 users since 2017, and our support team is available 24/7 if anything ever looks wrong with your account. If you're ready to sell crypto for naira with a team that will never ask for your codes, download the KWIQ app.