Area Code 2135 – Oslo
The phone area code for Oslo is 2135 (international format +472135). Browse local exchange codes (NXX) and carrier assignments below.
📞 Exchange Codes (NXX) for Area Code 2135
Select a central office code to view local carrier data and detailed information
📍 Geographic Location of Oslo
Overview of Area Code 2135
Area code 2135 is a geographic subscriber number range within the Oslo numbering plan of Norway. It is part of the country's national destination code (NDC) structure, where the leading digit '2' designates the capital region. Specifically, numbers beginning with 2135 are allocated to fixed-line services in Oslo and its immediate administrative surroundings. The code is administered under the Norwegian Communications Authority (Nkom) and follows the ITU-T E.164 international numbering standard.
Geographic Coverage and Administration
The 2135 prefix serves the central and eastern districts of Oslo, including boroughs such as Gamle Oslo, Grünerløkka, and Sagene. It covers both residential and business lines within these areas. As a geographic code, it is tied to a physical address, and the tariff for calls to 2135 numbers is based on the caller's location and the destination's fixed-line status. The code is not portable outside the Oslo exchange area, although number portability within the same geographic region is permitted.
Dialing Formats
For local callers within Norway, the number is dialed as an 8-digit national significant number (NSN): 21 35 XX XX. No trunk prefix '0' is used in Norway; instead, the national direct dialing prefix is omitted. For international callers, the full international format is required: +47 21 35 XX XX. The country code for Norway is +47, and the leading '2' of the area code is part of the NDC. When calling from abroad, you must drop any leading '0' (which is not used in Norway) and add the +47 country code.
Caller Instructions
- Local callers (within Norway): Dial the 8-digit number directly, e.g., 2135 1234.
- International callers: Dial the international access prefix (00 or +), then 47, then the 8-digit number, e.g., +47 2135 1234.
- From mobile phones: Always use the international format when dialing from a mobile, as it ensures correct routing.
Overlay and Numbering Considerations
Oslo has several area codes (2, 3, 6, 7, 8, 9) due to historical numbering assignments. There is no overlay code for 2135; it is a unique prefix within the 21 range. However, number portability allows subscribers to retain their 2135 number when switching providers within the same geographic area. This means that a 2135 number may be served by any fixed-line operator, but the geographic tariff remains based on the original exchange.
Practical Usage
Businesses and residents in the 2135 area often use these numbers for local customer service and administrative lines. When marketing to Oslo, having a 2135 number can enhance local presence. For VoIP users, the number functions as a geographic number, and emergency calls (112) are routed based on the registered address.