An unknown number is calling me: what to do step by step
You keep getting calls from a number you do not recognise. Learn how to identify the caller, verify the number before answering, and protect yourself from spam.
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An unknown number is calling me: what to do step by step
Getting calls from numbers you do not have saved is increasingly common. Before answering or calling back, it pays to check who is behind it: the NoCall community maintains a large database of user-contributed reports on phone numbers in Spain.
1. Do not answer with your data
If you decide to pick up, listen first. Do not say your full name, do not confirm your ID, and do not share codes arriving by SMS. A legitimate caller will identify themselves without asking for sensitive data upfront.
2. Look the number up on NoCall
The NoCall database holds a large catalogue of numbers identified by the community. For each number you can see its risk score, category, and comments from other users:
- Risk score — from 0 (safe) to 100 (dangerous).
- Category — spam, telemarketing, scam, debt collection, surveys.
- Comments — what other users who got the same call reported.
3. Read the prefix
The prefix gives you immediate clues about the kind of call:
- 6XX, 7XX — Spanish mobile phone.
- 91X–95X — Landline by province (91 Madrid, 93 Barcelona, 95 Seville...).
- +international prefix — International call: verify the country before calling back, it may be expensive.
4. Decide: call back, block, or ignore
- Low risk and a plausible reason — call back normally.
- Spam or pushy telemarketing — block the number and report it on NoCall.
- Possible scam — do not call back; if you already shared data, contact your bank and report it.
5. Protect yourself going forward
Turn on your phone spam filter and the NoCall app to identify incoming calls automatically. If the call felt suspicious, also read what to do about a suspicious call.
Should I answer a call from an unknown number?
You can answer, but never share personal or banking details. If the call matters, they will leave a message or call back. Afterwards, look the number up on NoCall to see if other users have reported it.
How can I find out who called me from an unknown number?
Look the number up on NoCall: you will see its risk score, category (spam, telemarketing, scam), carrier, and comments from other users who got the same call.
Is it dangerous to call back an unknown number?
It can be: some premium-rate numbers charge high fees when you call them. Always verify the number on NoCall before calling back.
Sources and review
Reviewed:
Numbering, carrier tools, and reporting procedures can change. Verify sensitive steps with the linked primary authority.
Article details
Editorial content reviewed by NoCall with practical context for spotting suspicious calls and messages.
Received a suspicious call?
Look up the number in NoCall before sharing data, calling back, or clicking any link.
Search a phone number or a company name (Iberdrola, Movistar and Vodafone...) to check if it has been reported as spam.