Area Code 2387 – Oslo

Overview of Area Code 2387

Area code 2387 is a geographic prefix within the Norwegian national numbering plan, assigned to the capital region of Oslo. In the context of Norway's telephony system, this code falls under the broader Oslo metropolitan area, which is served by several geographic prefixes. The prefix 2387 is part of the 2xxx range, which is predominantly allocated to the Oslo region, reflecting the city's historical and administrative significance as the country's political, economic, and cultural hub.

Coverage and Administration

The 2387 prefix covers specific districts within the municipality of Oslo, including central business areas and residential neighborhoods. As with all geographic codes in Norway, the prefix is administered by the Norwegian Communications Authority (Nkom), which oversees the national numbering plan in accordance with ITU-T E.164 recommendations. The jurisdiction for this code is the Oslo municipality, and the numbers are used for fixed-line services, typically provided by established telecom operators such as Telenor, Telia, and various alternative carriers.

Dialing Formats

For callers within Norway, dialing a number with the 2387 prefix requires the national trunk prefix '0' followed by the area code and the subscriber number. For example, a local Oslo number might be dialed as 023 87 45 67 (where the leading '0' is the trunk prefix). However, when dialing from abroad, the international format must be used: +47 23 87 45 67, omitting the leading '0'. The full international number includes the country code +47, the area code (without the trunk prefix), and the subscriber number, which together form a complete E.164 number of up to 12 digits.

Caller Instructions

For local callers within Oslo, it is common to dial the eight-digit subscriber number directly without the area code, as the city operates as a single local calling area. However, for callers from other regions of Norway, the full national format (023 87 45 67) is required. International callers must always use the +47 country code and drop the leading '0'. It is important to note that Norway has not implemented overlay codes in Oslo; instead, multiple geographic prefixes coexist, and the area code is an integral part of the subscriber number for routing purposes.

Numbering and Portability

Subscriber numbers under the 2387 prefix typically have eight digits, with the prefix forming the first four digits. Since the introduction of number portability in Norway, customers can retain their geographic numbers when switching service providers, even if they move to a different operator. However, geographic numbers are generally tied to a specific location, and porting does not change the geographic association. This ensures that the 2387 prefix remains a reliable indicator of a fixed-line connection in the Oslo area.