// Guides
SIM swapping: detect & defend
In SIM swapping, offenders take over your phone number (replacement SIM/eSIM) and intercept SMS-based confirmation codes — e.g. for online banking. A sudden loss of signal is the key warning sign.
Updated: 2026-06-19
Immediate steps
- 1On sudden, unexplained loss of signal, contact your mobile provider immediately (from another phone).
- 2Check and secure online banking and important accounts at once.
- 3Switch SMS-based two-factor authentication to an authenticator app.
- 4Set up a customer password/porting lock with your provider.
- 5Preserve evidence (timestamps, messages) and file a police report.
- 6Change passwords of affected accounts and review recovery options.
What not to do
- Do not dismiss a sudden loss of signal as a mere glitch.
- Avoid SMS as the only second factor for sensitive accounts.
- Do not use a weak or guessable customer password with your provider.
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Common questions
- How do I recognise SIM swapping?
- By a sudden loss of network/reception with no technical reason, followed by login or TAN notifications that are not from you.
- How do I protect myself in advance?
- An authenticator app instead of SMS codes, a strong customer password/porting lock with your provider, and vigilance on signal loss.
- My account was drained — what first?
- Inform your bank immediately and block the account, contact your provider, file a report and preserve all evidence.