Area Code 206 – Cao Bang province

Geographic Overview

The +84 206 area code is a geographic National Destination Code (NDC) assigned to the Cao Bang province in the northeastern mountainous region of Vietnam. This province shares a border with China's Guangxi Zhuang Autonomous Region and is known for its karst landscapes, waterfalls, and ethnic diversity. The area code covers the provincial capital, Cao Bang City, and all districts within the province, including Bao Lac, Ha Quang, Thong Nong, and Tra Linh.

Dialing Formats

For callers within Vietnam, the trunk prefix '0' is used before the area code. The national dialing format is 0 206 XXX XXXX, where '0' is the trunk prefix, '206' is the area code, and the subscriber number is typically 7 digits. For example, a landline in Cao Bang City might be dialed as 0 206 385 1234.

For international callers, the country code +84 is used, and the leading '0' is dropped. The international format is +84 206 XXX XXXX. For instance, a caller from the United States would dial +84 206 385 1234 to reach the same number.

Administrative and Regulatory Context

Under the Vietnamese numbering plan, geographic area codes are allocated by the Ministry of Information and Communications (MIC) and follow the ITU-T E.164 recommendation. The 206 code is part of the 2XX series reserved for fixed-line services in northern provinces. Subscriber numbers within this code are assigned by local fixed-line operators, primarily VNPT (Vietnam Posts and Telecommunications Group) and Viettel, who provide PSTN and VoIP services in the region.

Overlay and Numbering Considerations

As of the latest update, there is no overlay code for Cao Bang; the 206 code is the sole geographic code for the province. However, with the increasing adoption of VoIP and mobile services, some subscribers may have migrated to non-geographic numbers, but landlines retain the 206 prefix. When dialing within the same area code, callers can often omit the area code for local calls, but it is recommended to include it for clarity, especially when using mobile phones.

Caller Instructions

• Local callers (within Cao Bang): Dial the subscriber number directly (7 digits) if using a landline, or dial the full national format 0 206 XXX XXXX for reliability.
• Long-distance callers within Vietnam: Dial 0 206 XXX XXXX.
• International callers: Dial your country's exit code, then 84 206 XXX XXXX (e.g., from the UK: 00 84 206 XXX XXXX).

Always verify the current subscriber number length with your service provider, as numbering changes can occur.