Area Code 55 – Moravian-Silesian Region

Overview of Area Code 55 (Czechia)

Area code 55 is a geographic National Destination Code (NDC) assigned to the Moravian-Silesian Region in the eastern part of Czechia. This region is one of the country's most industrially significant areas, with its administrative center in Ostrava. The code covers a densely populated area that includes major cities such as Ostrava, Havířov, Karviná, Frýdek-Místek, Opava, and Nový Jičín. As a geographic code, it is used for fixed-line (PSTN) services, and numbers under this code are allocated to local exchange areas within the region.

Dialing Formats and Usage

When calling a fixed-line number in the Moravian-Silesian Region from within Czechia, you must use the national trunk prefix 0 followed by the area code and the subscriber number. The full national format is 0 55 XXX XXXX (or 0 55 XXX XX XX depending on the local number length). For example, a typical Ostrava number might be dialed as 0 55 123 4567.

From abroad, callers must use the Czech international prefix +420, drop the leading trunk prefix '0', and dial +420 55 XXX XXXX. For instance, an international caller would dial +420 55 123 4567 to reach the same number. It is important to note that Czechia uses closed numbering plan, meaning that the national significant number (NSN) is always nine digits, and the area code is not separated by a pause when dialing.

Geographic Coverage and Local Significance

The 55 area code is not a single city code but a regional code covering multiple telephone exchanges. The region is known for its coal mining and metallurgical history, and Ostrava is the third-largest city in Czechia. The code serves both residential and business customers, and due to the region's economic importance, many companies have headquarters or branch offices here. The area code is also used for fax lines and some legacy ISDN services.

Overlays and Numbering Considerations

Currently, there is no overlay code for the 55 area; the region is served solely by this NDC. However, as with all Czech geographic codes, number portability exists, meaning that a subscriber may retain their number when moving to a different operator, but the geographic significance remains tied to the original location. For callers, it is essential to always include the area code when dialing a fixed-line number, even for local calls, because Czechia uses a closed dialing plan. This means that local calls within the same exchange also require the full national number (including the area code).

For businesses, having a 55 number signals a local presence in the Moravian-Silesian Region, which can be beneficial for customer trust and local marketing. For individuals, understanding the correct dialing format ensures seamless connectivity with friends, family, or business contacts in this part of Czechia.