Area Code 228 – Nam Dinh province

Geographic Coverage and Administrative Jurisdiction

The area code +84 228 is the National Destination Code (NDC) assigned to the province of Nam Dinh, located in the Red River Delta region of northern Vietnam. This geographic code is used for fixed-line telephone services within the province, covering the provincial capital of Nam Dinh City and all surrounding districts, including Vu Ban, Y Yen, Nghia Hung, Truc Ninh, Xuan Truong, Giao Thuy, Hai Hau, and My Loc. The code is administered under the national numbering plan of Vietnam, which follows ITU-T Recommendation E.164.

Dialing Formats and Caller Instructions

For callers within Vietnam, the national trunk prefix 0 is dialed before the area code, followed by the subscriber number. The complete national format is 0 228 XXX XXXX (where X represents the local subscriber digits). For example, a local call to a Nam Dinh landline would be dialed as 0228 123 4567.

For international callers, the Vietnamese country code +84 is used, followed by the area code without the leading zero. Thus, the international format becomes +84 228 XXX XXXX. For instance, a caller from abroad would dial +84 228 123 4567 to reach the same number.

Numbering Structure and Overlay Considerations

Subscriber numbers within the 228 area code typically consist of 7 digits, making the total length of a national significant number (NSN) 10 digits (including the leading 0). As of the current numbering plan, there is no overlay code in Nam Dinh; the 228 code is exclusively used for geographic fixed-line services. However, due to the growth of VoIP and mobile services, some numbers may be routed over IP networks, but the geographic identity remains tied to the province.

Regulatory and Technical Notes

The assignment and management of the 228 code are overseen by the Vietnam Telecommunications Authority (VNTA) under the Ministry of Information and Communications. All fixed-line operators providing services in Nam Dinh, such as VNPT, Viettel, and FPT Telecom, utilize this code for their PSTN and VoIP-based fixed services. Callers should note that while mobile numbers in Vietnam use different prefixes (e.g., 03x, 05x, 07x, 08x, 09x), any number beginning with 0228 is definitively a geographic fixed-line number.

For businesses and residents, understanding the correct dialing format is crucial for seamless connectivity. Whether placing a local call from Hanoi or an international call from the United States, using the appropriate prefix ensures proper routing. Always verify the subscriber number length, as some older lines may have fewer digits, but the standard is 7 digits after the area code.