Area Code 521 – Casablanca/Central Morocco

Geographic Coverage and Administrative Jurisdiction

Area code 521 is a geographic National Destination Code (NDC) within the Moroccan national numbering plan, allocated under the international country calling code +212. It serves the economic capital, Casablanca, and its surrounding administrative jurisdictions within the Casablanca-Settat region. This includes the prefectures of Casablanca, Mohammedia, and parts of the wider metropolitan area, extending to nearby towns such as Nouaceur and Mediouna. The code is assigned to fixed-line PSTN services, and it is used by both residential and business subscribers.

Dialing Formats and Caller Instructions

For callers within Morocco, the national dialing format requires the trunk prefix 0 followed by the NDC and the subscriber number. Thus, a local call to a Casablanca fixed line would be dialed as 0521-XXX-XXX. For international callers, the country code +212 is used, and the leading trunk prefix is omitted. The international format is +212 521-XXX-XXX. For example, a number in Casablanca might be +212 521 234 567. It is important to note that when calling from abroad, you must replace the initial '0' with the +212 country code. Local callers within Casablanca can often dial the 8-digit subscriber number directly, but using the full national format is recommended for clarity and to avoid errors.

Numbering Plan and Overlay Considerations

The Moroccan numbering plan underwent a major restructuring in 2005, when the NDC was expanded from one digit to two digits. As a result, Casablanca's original code '2' was replaced by '20' for some regions and '21' for others. Specifically, Casablanca was assigned the two-digit NDC 21, and the third digit '5' was added to create the current three-digit area code 521. This change was necessary to accommodate the growing demand for telephone numbers. There is no overlay code in Casablanca; the 521 code is exclusive to the fixed-line network in this region. However, due to number portability, a subscriber may retain their 521 number even if they move to a different operator or, in some cases, relocate within the same region.

Technical and Regulatory Notes

The 521 code is managed by the Agence Nationale de Réglementation des Télécommunications (ANRT), Morocco's regulatory authority. All fixed-line numbers under 521 are 9 digits long when including the leading '0' in national format, or 8 digits after the country code in international format. The code is used for both traditional copper-line PSTN services and fiber-optic VoIP services, but it remains geographically tied to the Casablanca area. Callers should be aware that while VoIP services may allow location-independent use, the number itself is still associated with the Casablanca region for emergency services and caller ID purposes. For businesses, having a 521 number establishes a local presence in Morocco's commercial hub, which can be beneficial for customer trust and regional marketing.