Area Code 51 – Razavi Khorasan

Overview of Area Code +98 51

Area code 51 is the National Destination Code (NDC) for the province of Razavi Khorasan in northeastern Iran, as designated under the ITU-T E.164 international numbering plan. This geographic code is assigned to the provincial capital, Mashhad, as well as surrounding cities and towns within the administrative boundaries of Razavi Khorasan. The code is used for fixed-line (PSTN) services and is not associated with mobile networks, which operate under separate non-geographic prefixes.

Geographic Coverage and Major Cities

The +98 51 area code covers a vast region, including the metropolitan area of Mashhad, the second most populous city in Iran, along with other significant urban centers such as Neyshabur, Sabzevar, Kashmar, Gonabad, Torbat-e Heydarieh, and Quchan. The code serves both urban and rural subscribers within the province, with local numbers typically having a length of 8 digits after the area code, resulting in a total national significant number (NSN) of 10 digits when including the leading trunk prefix '0'.

Dialing Formats and Procedures

For callers within Iran, dialing a fixed-line number in Razavi Khorasan requires the trunk prefix 0 followed by the area code 51 and the local subscriber number. For example, a local number in Mashhad might be dialed as 0 51 3XXX XXXX. When calling from abroad, the international access prefix (e.g., 00 or +) is used, followed by Iran's country code 98, then the area code 51 without the leading zero, and the subscriber number. Thus, an international caller would dial +98 51 3XXX XXXX. It is important to note that the area code is an integral part of the national dialing plan; omitting it will result in a failed call.

Overlay and Numbering Considerations

Currently, there is no overlay code for the 51 area code, meaning that the region is served exclusively by this single geographic NDC. However, as demand for fixed-line services evolves, the regulatory authority may introduce additional numbering resources. Subscribers within the province must always include the area code when dialing from outside the local calling area, even when calling from a mobile phone. For international callers, it is essential to drop the trunk prefix '0' when using the +98 country code, as the international format does not include it.

Practical Guidance for Callers

When placing a call to Razavi Khorasan from another country, ensure you have the correct local number, including the area code. For example, to call a business in Mashhad with the local number 3XXX XXXX, you would dial +98 51 3XXX XXXX. If you are within Iran but outside the 51 area, dial 0 51 3XXX XXXX. Always verify the number length, as local numbers may vary. For further assistance, consult your telecom provider or the official numbering plan resources.