Prefix 351: Complete Guide and Essential Information

Have you ever received a call from an unknown number with the prefix 351 and wondered where it came from? In this case, it is crucial to distinguish between +351 and 351 (without the “+”). The international prefix +351 identifies a call coming from Portugal, while 351 without the “+” could indicate an Italian number from the operator Iliad. If you are planning a trip to Portugal or simply want to know more about this prefix, this complete guide will provide you with all the necessary information: from its origin and usage to curiosities, regulations, and potential pitfalls surrounding it. Get ready to dive into the world of telecommunications and become an expert on the prefix 351!

What is the prefix 351 and how is it used?

The prefix 351 is a numeric code that precedes the phone number and identifies Portugal in international communications. This prefix plays a crucial role in the correct routing of phone calls. To call a phone number in Portugal from abroad, you must dial the international prefix +351 followed by the local phone number. For example, to call the number 123456789 in Portugal from Italy, you would dial +351 123456789. To make international calls from Portugal to other countries, dial the prefix “00” followed by the destination country code and the local phone number. The prefix 351 applies to all phone numbers in Portugal, including mobile numbers.   

The prefix 351 and Iliad in Italy

As mentioned in the introduction, the prefix 351 can also appear in phone numbers of Italian mobile operators, such as Iliad. In this case, the prefix 351 does not indicate a call coming from Portugal, but simply a number assigned by Iliad to its customers in Italy. The fundamental difference lies in the presence or absence of the “+” sign. If the number starts with +351, it is a call coming from Portugal. If, however, the number starts with 351 without the “+”, it is an Italian Iliad number.

Comparison with other mobile phone prefixes

In addition to Iliad’s 351, there are numerous other mobile phone prefixes in Italy, each associated with a different operator:

Prefix	Operator
347	Vodafone Italia
330 – 339, 360, 363, 366, 368	TIM
320, 323, 327, 328, 329, 380, 383, 388, 389	Wind Tre
351	ILIAD
390 – 393, 397	3 Italia

Number portability and prefix 351

In Italy, phone number portability allows you to change phone operator while keeping your phone number. This means that a phone number with the prefix 351, originally assigned by Iliad, could have been subsequently transferred to another operator. Consequently, it is not always possible to associate a number with the prefix 351 to the operator Iliad with certainty. To avoid receiving unwanted calls from any call center number, you can register your number in the Public Opposition Registry.

Curiosities about the prefix 351

• The prefix 351 was assigned to Portugal by the International Telecommunication Union (ITU) as part of the international telephone numbering plan.   
• Phone scams: Recently, the prefix 351 has been used in several phone scams aiming to steal sensitive user data. These scams often involve calls with recorded messages inviting the user to save the number and continue the conversation on WhatsApp. Once the victim contacts the scammer, the latter starts requesting personal information such as documents, bank details, or access codes, under the pretext of offering a job or for other reasons. Another scam associated with the prefix 351 is the “wangiri”. In this case, the user receives a call from a number with a foreign prefix that rings only once. The missed call intrigues the user, who calls the number back, unaware that it is a premium service with very high rates.   

Phone operators in Portugal

MEO (Altice Portugal): Originally Portugal Telecom, MEO is the main telecommunications operator in Portugal. Founded in 1994 as a state-owned company, Portugal Telecom initially held the monopoly on fixed telephony in the country. Over the years, the company expanded into the mobile telephony, internet, and television markets. After the liberalization of the telecommunications market in Portugal and the abolition of the government’s “golden shares” in 2013, Portugal Telecom merged with the Brazilian operator Oi. In 2015, the company was acquired by the Dutch group Altice and changed its name to Altice Portugal, keeping the MEO brand for its services.   

Other operators

• NOS: a major telecommunications operator in Portugal, offering fixed telephony, mobile, internet, and television services.
• Vodafone Portugal: part of the Vodafone group, offering mobile telephony, internet, and television services.

Rules and regulations

The use of the prefix 351 in Portugal is subject to the rules and regulations established by the National Communications Authority (ANACOM), the telecommunications regulator in Portugal. ANACOM is responsible for ensuring competition in the telecommunications market, consumer protection, and compliance with European regulations on electronic communications. Among its functions, ANACOM manages the assignment of telephone numbers, defines technical standards for telecommunications networks, and monitors compliance with rules to protect users.   

Comparative and summary table

Feature	Description
Prefix	351 or +351
Nation	Portugal or Italy
Type of numbers	Fixed and mobile
Usage	National and international calls
Examples of calls	From Italy: +351 123456789 From Portugal to Italy: +39 123456789
Emergency numbers	112 (European Emergency Number)
Main operators	MEO, NOS, Vodafone and Iliad (in Italy)
Regulatory entity	ANACOM (National Communications Authority in Portugal) AGCOM in Italy

Conclusions

The prefix 351 represents a key element in the global communication system. Its main function is to identify Portugal as the destination for phone calls, allowing the correct routing of communications to this country. However, its use also extends to identifying some phone numbers of the operator Iliad in Italy.

The prefix 351 is strictly linked to Portugal’s identity in the world of telecommunications. Its presence in phone numbers contributes to creating a unified image of the country internationally.

However, the growing spread of the prefix 351 has also led to the emergence of new challenges, particularly regarding user security. The use of this prefix in various phone scams requires special attention from those receiving calls from unknown numbers. It is fundamental to be aware of these threats and take the necessary measures to protect one’s personal data.

Ultimately, the prefix 351 is a fundamental element for communication with Portugal and for the identification of some Iliad numbers in Italy, but it also requires greater awareness from users. Knowing its meaning, its usage, and the potential pitfalls associated with it is essential for effective and secure communication.

Frequently Asked Questions