Area Code 454 – Tvarditsa, Sliven
The phone area code for Tvarditsa, Sliven is 454 (international format +359454). Browse local exchange codes (NXX) and carrier assignments below.
📞 Exchange Codes (NXX) for Area Code 454
Select a central office code to view local carrier data and detailed information
📍 Geographic Location of Tvarditsa, Sliven
Geographic Coverage and Administrative Jurisdiction
The +359 454 area code is a geographic National Destination Code (NDC) assigned to the town of Tvarditsa and its surrounding municipalities within the Sliven Province of central Bulgaria. Tvarditsa is situated in the southern foothills of the Balkan Mountains (Stara Planina), near the eastern end of the famous Shipka Pass. The code serves the administrative territory of Tvarditsa Municipality, which includes the town itself and several adjacent villages, such as Banya, Zhalt Bryag, and others. This allocation is managed by the Communications Regulation Commission (CRC) of Bulgaria, which follows the national numbering plan aligned with ITU-T E.164 recommendations.
Dialing Formats and Caller Instructions
For local callers within Bulgaria, the number is dialed in the national format: 0 454 XXX XXX (where X represents the subscriber's local number digits). The leading '0' is the trunk prefix used for domestic calls. When calling from abroad, the international format is used: +359 454 XXX XXX. In this case, the trunk prefix '0' is omitted, and the country code +359 is used. For example, a local call to a subscriber in Tvarditsa would be dialed as 0454 123 456, while an international caller would dial +359 454 123 456. It is important to note that the area code is an integral part of the full national significant number, which is 9 digits in length (excluding the trunk prefix).
Overlay and Numbering Considerations
Currently, there is no overlay plan for the 454 area code, meaning that the geographic region is served exclusively by this code. However, number portability is available in Bulgaria, allowing subscribers to retain their numbers when switching between fixed-line operators within the same geographic area. The geographic nature of the code means that the tariff for calls to +359 454 numbers is typically based on the distance and the operator's pricing policy, but with the liberalization of the telecom market, many operators offer flat-rate national calling plans that include such geographic numbers.
Services and Usage
Subscribers within the 454 area are primarily served by fixed-line PSTN and VoIP services. The region is characterized by a mix of residential and business users, including local administration, small enterprises, and agricultural businesses. As with other Bulgarian geographic codes, the numbers are used for both voice and data services, including ADSL and fiber-optic internet connections that are often bundled with telephony. For callers from outside Bulgaria, it is essential to use the correct international prefix (e.g., 00 from most European countries, or 011 from North America) followed by the country code and area code without the leading zero.