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Commercial calls change on 17 October: if you see a 400, you'll know who's calling
Commercial calls will have a new way of identifying themselves in Spain. From 17 October, companies will have to use numbers in the 400 range for this type of communication. In addition, users will be able to ask their operator to block these calls.
Checking the number before answering an unknown call will become a bit more useful from 17 October 2026. From that date, commercial calls will have to be made using a specific number range starting with 400.
The aim is for consumers to easily distinguish a commercial call from other types of company communications, such as customer service or after-sales services.
If it starts with 400, it’s a commercial call
The key will be easy to remember: the 400 range will be reserved exclusively for commercial calls.
The numbers will have nine digits and will appear on your phone screen like any other call. The difference is that, by recognising the 400, users will be able to know in advance what kind of call they are receiving.
This numbering cannot be used for customer service or other purposes.
You won’t be able to call back
There’s another important detail: 400 numbers will only work for outgoing calls.
This means a company can call from one of these numbers, but the consumer won’t be able to call the same number back. The regulations state that calls cannot be made to numbers in the 400 range.
Customer service will continue to use other numbers, such as 800 and 900, geographic numbers, or certain short numbers set up for that purpose.
Can all 400 calls be blocked?
The regulations allow users to request their operator to block commercial calls made through the 400 range.
It won’t necessarily be an automatic block. The consumer will have to request it, and the operator must offer this option so the service can be activated.
In this way, as well as making it easier to identify who is calling, there will be a way to directly avoid commercial communications made using this numbering.
When does the change start?
The new numbering will be fully operational from 17 October 2026.
The resolution assigning the 400 range was published in the Boletín Oficial del Estado on 16 April and set a six-month period to implement the system.
From then on, and except for the exceptions set out in the regulations, commercial calls must be made using the 400 range. So from 17 October, there’s a number worth remembering: if the call starts with 400, its purpose is commercial.