Does *#21# Show If Your Phone Is Tapped?
Last checked: 8 September 2026
No. *#21# is a call-forwarding status request, not a phone-tapping detector. A successful response tells you about a service setting. It cannot establish that the phone is free of spyware or that someone is listening to calls.
What the result means
| Response | Useful interpretation | What it does not establish |
|---|---|---|
| Enabled or forwarded | A forwarding setting is active for the service shown | That the destination is malicious |
| Disabled or not forwarded | That queried forwarding service is inactive | That the phone or account is secure |
| Failed or invalid MMI | The request did not complete successfully | That forwarding is on or off |
Read the service label as well as the number. Some interfaces show several legacy service categories. A label mentioning data does not mean web browsing is being copied, and these codes do not audit messaging-app sessions.
Why a voicemail number may appear
Missed calls can legitimately be routed to voicemail. If you are investigating a destination, use the provider's help or account support to identify it. Do not assume that an unfamiliar number is an attacker, and do not ring a suspicious destination to investigate it.
If you see a destination nobody responsible for the line recognises, record the setting and ask the network to confirm its purpose. On a managed work phone, involve the business administrator before changing routing that other staff may rely on.
Review the right settings
On iPhone, Apple's forwarding guide separates calls, text messages and email. Check Settings > Apps > Phone > Call Forwarding for calls. Text Message Forwarding is under Messages and concerns the devices linked to the Apple Account. These are distinct checks.
For a wider concern, review signed-in devices and unfamiliar account activity using the manufacturer's account settings, apply current software updates, and seek help from your IT administrator or the provider. A forwarding code should never be the only check used to dismiss a concern.
Do not use a blanket cancellation as a security fix
The internet often pairs *#21# with a cancellation code described as an instant fix. Cancelling routing may remove legitimate voicemail and office diverts. It does not inspect installed apps, secure an account or remove malware. Follow the call-forwarding guide if changing a confirmed divert is actually what you need.
Frequently asked questions
Is it safe to check *#21#?
The standard command requests status rather than changing routing. It may be unavailable on your service; keep any displayed destination details private.
Does a disabled result mean nobody can monitor my phone?
No. The result only concerns the queried forwarding setting and says nothing about installed software or account access.
Will cancelling all diverts remove spyware?
No. It changes call-routing registrations on a supporting service and can disrupt voicemail. It is not a malware-removal procedure.
Sources
- ETSI: supplementary-service status requests
- Apple: calls, texts and email forwarding checks
- Android: call-diversion support
Related guides
- Latest business phones
- Compare phones for your team
- UK phone codes explained
- Call forwarding codes and settings
- Find your IMEI with *#06#
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