How to find out who is calling from an unknown number

Unknown calls are common in Spain. Before you call back, check whether other people have already identified the number. The NoCall community has collected more than 0 reports on Spanish phone numbers.

1. Search the number on NoCall

The fastest way to understand a call. NoCall maintains a database with more than 54,548 numbers flagged by the community. For each number you can see:

Risk score — from 0 (safer) to 100 (high risk).
Category — spam, telemarketing, scam, debt collection, surveys.
Carrier and line type — mobile, landline, premium-rate.
Comments — what others experienced from the same caller.
Search interest — how often the number has been looked up recently.

2. Read the prefix

The prefix tells you a lot about the kind of line:

6XX, 7XXMobile

91X–95XLandline (by area: 91 Madrid, 93 Barcelona, 95 Seville, and so on)

800, 900Toll-free numbers (companies and support lines)

803–807Premium / special-rate services — high per-minute cost

901, 902Shared-cost numbers (extra charges when you call back)

On NoCall you can browse numbers for a whole prefix. For example, numbers starting with 911 or numbers starting with 900.

3. Check whether it matches a known company

Many businesses publish their official numbers online. If the caller ID matches your bank or a provider, it might be legitimate — but scammers can spoof well-known numbers. When in doubt, hang up and dial the number from the company’s official website or contract.

4. Do not call back blindly

If you find nothing and do not recognise the number, do not return the call. Some premium prefixes (803, 806, 807) can be very expensive. Genuine callers will try again or reach you another way.

5. Automate protection

With the NoCall app, numbers that are already reported as spam can be blocked automatically. You do not have to research every unknown caller manually — the app helps shield you from more than 54,548 known spam numbers.

Had a call from an unknown number?

Look it up in our database with more than 0 community reports:

Frequently asked questions

How can I find out who called from an unknown number?+

Search the number on NoCall — more than 0 real user reports help you tell spam, telemarketing, or a scam apart. You can also check the prefix for line type and carrier.

What do Spanish phone prefixes mean?+

6XX and 7XX are mobiles, 9XX are landlines (by area), 800 and 900 are toll-free, 803/806/807 are premium-rate with high cost, and 901/902 add extra charges when you call.

Is it safe to call back an unknown number?+

Not without checking first. Some premium-rate numbers charge high fees when you return the call. Always search the number on NoCall before calling back.