Area Code 212 – Oslo

Overview of Area Code 212 (Oslo, Norway)

Area code 212 is a geographic National Destination Code (NDC) within the Norwegian telephone numbering plan, assigned to the capital city of Oslo and its immediate surroundings. As part of the +47 country code, Norway employs a closed numbering plan, meaning that the full national significant number (NSN) is always eight digits long, including the leading '2' of the area code. Thus, local numbers in Oslo are written as 21 23 45 67 in national format, and as +47 21 23 45 67 in international format.

Geographic Coverage and Administrative Jurisdiction

The 212 prefix is allocated to the central and eastern districts of Oslo, covering the city centre, major business districts, and residential areas. It is one of several geographic codes serving the Oslo region, alongside 22, 23, 24, and 21 (which is shared with other parts of the greater Oslo area). The code is administered by the Norwegian Communications Authority (Nkom) and is assigned to fixed-line operators, including Telenor, Telia, and various alternative carriers. Subscribers may be served via traditional PSTN lines, ISDN, or VoIP-based fixed services, but the number remains geographically tied to the Oslo exchange area.

Dialing Formats and Caller Instructions

• Local callers (within Norway): Dial the eight-digit national number directly, e.g., 21 23 45 67. No trunk prefix is used.
• International callers: Dial the international access prefix (00 or +), then the country code 47, followed by the eight-digit number, e.g., +47 21 23 45 67. Do not add any extra '0' before the area code.
• Callers from mobile phones in Norway: May dial the number in national format; the call will be routed as a geographic fixed-line call.

Overlay and Numbering Considerations

Oslo does not have an overlay code; instead, multiple geographic NDCs (21, 22, 23, 24) coexist to provide sufficient numbering capacity. Because the NSN is always eight digits, there is no need for area code differentiation when dialing within Norway. However, the distinction is important for routing and for identifying the geographic origin of a number. Number portability allows subscribers to retain their 212 number when changing operators, but the number remains associated with the Oslo geographic area.

Practical Usage

Area code 212 is commonly used by businesses, government offices, and residents in Oslo. When displaying a number on websites or business cards, it is recommended to use the international format +47 21 23 45 67 to ensure clarity for both domestic and international callers. For international callers, always remember to replace the leading '+' with the appropriate international access code from your country (e.g., 011 from the US, 00 from most European countries).