Learn how to spot suspicious prefixes and protect yourself online. Follow these tips to stay safe and secure.Telephone scams are still with us, despite the Government’s attempts to put a stop to it with some measures that have not managed to put an end to this problem. Mobile devices also have some functions that allow, to a certain extent, to reduce the number of incoming calls or even block them.
But all this is still insufficient if we take into account the volume of unwanted communications (with a certain whiff of commercial intent or even fraud) that we receive daily.Can you tell if a number is SPAM before you pick up the phone? Here are a few steps you can take to eliminate unwanted calls , or at least avoid falling into the trap as few times as possible.
How to know if a number is SPAM before picking up the call
Pay attention to the prefix from which they call you
If the prefix from which you are being called does not match that of your country, in the case of Spain it is +34, be suspicious. Unless you have something pending in another country (a relative, a friend, a hotel reservation, etc.), it is not common to receive calls from Lithuania (+370), Tanzania (+255) or even Vanuatu (+678).
These are the most common:
- +27 (South Africa)
- +216 (Tunisia)
- +218 (Libya)
- +225 (Ivory Coast)
- +233 (Ghana)
- +234 (Nigeria)
- +255 (Tanzania)
- +33 (France)
- +355 (Albania)
- +370 (Lithuania)
- +371 (Latvia)
- +373 (Moldova)
- +375 (Belarus)
- +381 (Serbia)
- +383 (Kosovo)
- +44 (United Kingdom)
- +53 (Cuba)
- +563 (Valparaiso)
- +678 (Vanuatu)
There are numerous lists on the Internet with all the prefixes in the world, in fact, Wikipedia itself has one .
As an exception, a number starting with +353 may actually be a real call. This is the prefix for Ireland and many Amazon calls regarding orders come from here.It is also important to mention that there are methods to falsify the prefix. This technique is known as spoofing and what it does is “replicate” the Spanish prefix so that we trust the origin of the call.
Commercial calls can only come from these prefixes
The Government has just implemented a measure to make it even more difficult for commercial calls. From February 2025, commercial calls can only be made from a prefix in a Spanish province or from the 800 or 900 prefixes .Therefore, commercial calls from mobile phone numbers are prohibited. If users continue to receive them, they can report the incident to the Telecommunications Consumer Service Office.
Do a quick Google search
We all suffer from unwanted calls and users can help each other by entering these numbers in forums, websites, etc.Thanks to this, in most cases it is enough to search for the phone number on Google or any other search engine you use to find out if it is a spam number, even where they say they are calling from. There are specific directories for this, such as TrueCaller or ListaSpam . In fact, TrueCaller even has a Telegram channel to obtain, in a very fast and complete way, all the information about who is calling us.
Use Android SPAM call filters
If you use Android, you can activate SPAM call filters from the Google Phone app . It is a very useful and easy-to-use option that directly prevents calls from suspicious numbers from coming through.
There are also other third-party applications, such as Call Blocker or NO ESpam , which are created specifically so that when a call is missed you can see a SPAM warning or even create your own blacklists.
Create a blacklist on your mobile
Both Android and iOS incorporate the option to natively create your own blacklists, even for SMS . This has a disadvantage, and that is that they are created at the device level, so when you change your phone, that extensive list of phones that you have been carefully blocking will once again be free of filters.
What to do to avoid falling victim to a telephone scam
It is possible that, even with the utmost care, you may end up picking up the call thinking it is from a potential new job or a courier. If this happens, it is very easy to identify from the first few seconds that it is a SPAM call, either with the aim of selling you something or scamming you.
In this case, here are some tips to help you proceed in the best possible way.
Never provide personal data
Never, ever, under any circumstances, give out any personal information. Not your name, not the company you use for internet or electricity, not even information that seems trivial, like how many people live in your home.
Of course, sensitive data such as bank numbers, identification documents or your home address should never be given over the phone unless you are the one who initiated the call or if you are not 100% sure that it is essential and that the origin of the call is real.
Beware of vishing
As explained by INCIBE , it is a type of social engineering scam by telephone in which the identity of a third party is impersonated, whether it be a person, a company, etc.
If you get a call telling you that you have won a prize, that you are being contacted by a company’s technical support service or even that there is a problem with your bank account, be wary.
Be wary of the “double call”
The “yes” fraud is another dangerous telephone scam. When we use this word, either when picking up the phone or at any time during the conversation, the other party can let us know that they have recorded our voice to use as consent to sign us up for certain services or make purchases we do not want.
Once this concern has been generated, they call us again to “cancel” the operation. Under the pretext of helping us, they make us feel vulnerable and it is easier for us to end up giving out personal data that we should never provide.
Never return a call
The Wangiri technique is a very common scam that can be very expensive. You get a missed call and, when you go to return it, you are actually calling a premium rate number and the prank will cost you a few euros, which you will see reflected in your phone bill.
Sign up for the Robinson List
Although not always taken into consideration, signing up for the Robinson List can help significantly reduce the number of incoming calls.
If they keep calling you, from the very beginning of the conversation, tell your interlocutor that you are on this list and that they should not call you again. Sometimes it works.
First of all, common sense
We live in a time when cyber and telephone scams are increasingly present and use more sophisticated techniques to get us to take the bait. In addition to all the advice we have given you, nothing works better than common sense. Just as you would not carry your backpack open on the street, do not open your world through the screen or a phone.
