Area Code 904 – Mobile Network
The phone area code for Mobile Network is 904 (international format +421904). Browse local exchange codes (NXX) and carrier assignments below.
📞 Exchange Codes (NXX) for Area Code 904
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Overview of +421 904
The +421 904 prefix is a non-geographic mobile network code assigned to mobile services in Slovakia. Unlike geographic area codes, which correspond to specific cities or regions, 904 numbers are not tied to a physical location. They are used exclusively for mobile communications, enabling voice calls, SMS, and data services across the country and internationally. The prefix is part of the national numbering plan administered by the Slovak Regulatory Authority for Electronic Communications and Postal Services (RU), following ITU-T E.164 recommendations.
Technical Characteristics
Slovak mobile numbers, including those starting with 904, have a total length of 9 digits when dialed nationally, excluding the international access code. The structure is: 0 904 XXX XXX (national format) or +421 904 XXX XXX (international format). The prefix 904 is allocated to a specific mobile network operator, but due to mobile number portability (MNP), the prefix does not guarantee the current operator. When calling a 904 number, the caller is connected to the subscriber's current network, regardless of the original allocation.
Dialing Instructions
- Local callers (within Slovakia): Dial the national trunk prefix 0, followed by 904 and the subscriber number. For example, to call a number with the last seven digits 123 4567, dial 0904 123 4567.
- International callers: Dial the international access code (00 or +), then 421 (Slovakia's country code), then 904 and the subscriber number, omitting the leading 0. For example, from the US, dial 011 421 904 123 4567; from most European countries, dial 00 421 904 123 4567 or use the plus sign: +421 904 123 4567.
Usage and Services
Numbers with the 904 prefix are used for a wide range of mobile services, including personal and business voice calls, SMS, MMS, and mobile broadband. They support standard mobile features such as call forwarding, voicemail, and international roaming. Because they are non-geographic, they are suitable for individuals and businesses that require a mobile presence without being tied to a specific location. For businesses, 904 numbers can be used as primary contact numbers for employees, or as dedicated lines for customer service, though they are not typically used for toll-free services.
Regulatory and Cost Considerations
Calls to 904 numbers are charged according to the caller's mobile or fixed-line tariff. For callers within Slovakia, rates vary depending on the operator and plan; calls from fixed lines are typically higher than mobile-to-mobile rates. International callers are subject to international rates set by their own service providers. There are no special premium charges associated with 904 numbers; they are standard mobile numbers. When dialing from abroad, it is essential to use the correct international format to avoid misrouting.