Area Code 205 – Lang Son province
The phone area code for Lang Son province is 205 (international format +84205). Browse local exchange codes (NXX) and carrier assignments below.
📍 Geographic Location of Lang Son province
Geographic Overview
The +84 205 country calling code and area code combination corresponds to the fixed-line telephone network serving Lang Son province, a mountainous border province in northeastern Vietnam. Lang Son shares an international border with China's Guangxi Zhuang Autonomous Region and is strategically important for trade and logistics. The province's administrative center, Lang Son City, along with districts such as Cao Loc, Chi Lang, Van Lang, and Trang Dinh, are covered under this geographic prefix. Subscribers within this area are assigned numbers in the format +84 205 XXX XXXX, where the total number of digits after the country code is nine.
Dialing Procedures
For callers dialing from within Vietnam, the trunk prefix '0' is used before the area code, resulting in the national format 0205 XXX XXXX. For example, a local call to a fixed line in Lang Son would be dialed as 0205 XXX XXXX. When calling from abroad, the international access prefix (typically '00' or '+') is followed by the country code 84, then the area code without the leading zero, and finally the subscriber number: +84 205 XXX XXXX. It is important to note that the area code 205 is not an overlay; it exclusively serves Lang Son province. Callers should always include the area code when dialing from outside the province, even if the destination is within the same province but from a different local network.
Regulatory and Technical Notes
Vietnam's numbering plan is administered by the Ministry of Information and Communications (MIC) in accordance with ITU-T E.164 recommendations. The 205 prefix is classified as a geographic National Destination Code (NDC), and its use is restricted to fixed-line services provided by licensed PSTN operators. As of recent years, Vietnam has been transitioning its fixed-line infrastructure to support VoIP technology, but the geographic significance of the code remains unchanged. Subscribers in Lang Son may also have access to non-geographic services, but these would use different prefixes. For international callers, it is essential to verify the correct country code and area code to avoid misdialing, especially given the proximity to China and the potential for cross-border mobile networks to cause confusion.