400 Number for Business Calls in Spain: Reserve Yours Before the Ban
The 400 number is Spain’s new mandatory prefix for all outbound commercial calls, introduced under Law 10/2025 on Customer Service (Ley de Servicios de Atención a la Clientela).
From 17 October 2026, Spanish telecom operators will block any commercial call that doesn’t use this prefix. Neotel handles your application and reserves your 400 number as part of a limited allocation, integrated with your Virtual PBX.
The ban takes effect on 17 October 2026. 400 numbers are allocated to telecom operators in limited blocks, on a first-come, first-served basis — not directly to businesses. Reserve your place with Neotel now — limited availability.
What is a 400 number?
A 400 number is a new nine-digit, one-way number created specifically to identify outbound commercial calls made by businesses in Spain.
Unlike a normal phone line, it can only be used to make calls — the person receiving it cannot call it back. This is designed to let consumers instantly recognise a sales call and decide whether to answer, and to prevent “wangiri” scams, where a missed call tempts someone into ringing back a premium-rate number.
Legal basis and key date
Law 10/2025 on Customer Service (Ley de Servicios de Atención a la Clientela), passed in December 2025.
Resolution of 14 April 2026 from Spain's Secretary of State for Telecommunications and Digital Infrastructure, published in the BOE — Spain's Official State Gazette — as BOE-A-2026-8409, which allocates the 400 number range and sets the rules for its use.
Telecom operators have been able to request blocks of 1,000 400-numbers since April 2026.
Key date: 17 October 2026. From that day, operators will block commercial calls that don't come from a 400 number.
Oversight: the CNMC (Spain's National Markets and Competition Commission, the telecoms regulator) and the AEPD (Spain's data protection authority).
What happens if your business doesn't have a 400 number from October?
- The call will be blocked by the recipient's operator — it simply won't go through. Every outreach attempt is lost.
- Reputational and compliance risk with clients, partners and auditors.
- Exposure to CNMC and AEPD oversight under Law 10/2025.
- Missing the window: numbers are allocated to operators in blocks, on a first-come, first-served basis — the earlier you reserve, the more likely you are to be covered in time.
Who does this affect?
Any business that makes outbound commercial calls, including:
- Telemarketing and telesales
- Banking and financial services
- Insurance
- Energy and utilities
- Telecoms
- Any company with a sales or call centre team that proactively contacts customers or prospects
400 number vs 900 line: what's the difference?
Neotel’s call centre software is designed for B2B and B2C businesses that handle a significant volume of phone communications and need to professionalise, measure and scale their operations. Among the most common customer profiles:
Features
400 Number for Business
900 Line
Geographic number
Regular mobile number (6XX/7XX)
Call direction
Outbound only
Inbound only
Inbound and outbound
Inbound and outbound
Main use
Commercial calls / telesales
Customer service, support
General business use
Inbound call management, ACD, queues and IVR with real-time reporting
Caller ID on the recipient's phone
Shows as a commercial call
Doesn't identify the reason for the call
Doesn't identify the reason for the call
Doesn't identify the reason for the call
Mandatory?
Mandatory from 17 Oct 2026 for outbound commercial calls
Not mandatory (recommended for customer service)
Not applicable
Banned for commercial calls from 17 Oct 2026
Who needs it
Telemarketing, banking, insurance, energy, and any business with a telesales team
Businesses with customer service or support
Businesses with a local or regional presence
Personal use by staff; not valid for telesales from October onward
Running a business in Spain as an English speaker?
How to get your 400 number with Neotel
1. Reserve your place using the form on this page.
2. Our team submits your application to the operator as soon as your allocation window opens.
3. We activate your 400 number directly in your Neotel Virtual PBX.
4. A quick briefing for your sales team on how it works (one-way calls, how it appears on the recipient’s phone).
Faqs about Call Center Software
What is a 400 number?
A 400 number is a new nine-digit, one-way number created in Spain to clearly identify outbound commercial calls made by businesses. Unlike a normal phone line, it can only be used to make calls — the person who receives it cannot call it back.
When does the 400 prefix become mandatory?
The requirement takes effect on 17 October 2026. From that date, Spanish telecom operators will automatically block any commercial call that isn't made from a number with the 400 prefix.
What happens if my business keeps calling from a normal number after 17 October?
The call will be blocked by the recipient's operator and won't go through. The CNMC and the AEPD also oversee compliance with Law 10/2025 on Customer Service, which is where this requirement comes from.
What's the difference between a 400 number and a 900 line?
They serve opposite, complementary purposes. A 900 line is a free inbound number, designed so your customers can call you at no cost (customer service, support). A 400 number is for outbound use: it lets your business make commercial calls while letting the recipient instantly recognise it as a sales call. Many businesses will need both.
Which businesses are required to use a 400 number?
Any business that makes outbound commercial calls: telemarketing, banking, insurance, energy, telecoms, and generally any company with a sales or telesales team that proactively contacts customers or prospects.
Can I keep making commercial calls from a regular mobile number?
Not after 17 October 2026. The resolution governing the 400 number expressly bans the use of any other number, landline or mobile, for outbound commercial calls. If your sales team currently calls from ordinary mobile numbers (Spanish 6XX/7XX ranges) — as many call centres do — you'll need to migrate to a 400 number before that date.
Can a 400 number be called back?
No. 400 numbers are one-way: they can only be used to make outbound calls, not receive them. This design prevents "wangiri" scams, where a missed call tempts someone into calling back a premium-rate number.
How do I get a 400 number for my business in Spain?
400 numbers are allocated by the CNMC to telecom operators, in blocks and on a first-come, first-served basis — not directly to individual businesses. Neotel handles the entire application with our operator and integrates the number into your Virtual PBX. Because the allocation is limited, we recommend reserving your place as early as possible.
Does it cost anything to get a 400 number through Neotel?
Final pricing will be confirmed once the pack is available. Reserving your place now guarantees priority and preferential terms at launch, with no obligation to purchase.
Reserve your 400 number before 17 October
Reserve my 400 number
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