Never share a WhatsApp registration code. Turn on two-step verification and protect your mobile-carrier account separately. If someone else registers your number, WhatsApp says to register it again with the code sent by SMS or call; this logs out the other user. WhatsApp’s account recovery instructions explain the process.

Protect the WhatsApp account and phone line

A code scam targets you: someone may pose as a contact or send a message claiming a code was requested by mistake, then persuade you to hand it over. A SIM swap targets control of your number: a carrier transfers it to a SIM controlled by someone else, potentially redirecting calls and texts, including verification messages. Infobae describes both routes and identifies unexpected service loss and unsolicited verification requests as warning signs. Infobae’s account of the risks cites ESET Latinoamérica researcher David González on account takeover.

The protections work at different points. WhatsApp’s optional two-step verification adds a credential when your number is registered. A SIM PIN protects the SIM locally, while carrier-account protections address changes to the mobile line. None is a reason to share a WhatsApp code.

  1. Keep registration codes private. Don’t send a code to someone who asks for it, even if they claim it arrived by mistake. Verify unexpected requests through a separate channel.
  2. Turn on WhatsApp two-step verification. It adds a credential beyond the code used to register your number. WhatsApp explains the feature.
  3. Add a recovery email you can securely access. WhatsApp’s guidance describes email as a way to reset a forgotten two-step credential.
  4. Protect your carrier account. Use its account password, and ask your carrier whether it offers safeguards against unauthorized SIM changes or number transfers. Options vary by operator.
  5. Treat a SIM PIN as a separate safeguard. It is a local SIM control, not a substitute for protecting your carrier account or enabling WhatsApp’s additional registration credential.

If your mobile service suddenly stops

Unexpected loss of service can be a warning sign of an unauthorized line change, but it does not by itself prove that a SIM swap occurred. Contact your carrier through a known official channel and ask it to check for a SIM replacement or number-transfer request. If WhatsApp access is also lost, follow its number-registration recovery process.

Recover a number registered by someone else

  1. Register your phone number in WhatsApp again. Enter the verification code you receive by SMS or phone call. WhatsApp says this logs out the other user. Read WhatsApp’s compromised-account guidance.
  2. Use the recovery email if WhatsApp asks for a two-step credential you don’t know. WhatsApp’s reset guidance describes an email-based route. If you can’t use the recovery email, the cited instructions say you can reset the credential after a seven-day wait. See WhatsApp’s reset guidance.