The international dialing code for Vietnam is +84. To call Vietnam from the United States or Canada, dial 011 + 84 + area code + local number. From Europe, dial 00 + 84 + area code + local number. On mobile phones worldwide, use +84 followed by the area code and local number.
From USA/Canada: 011 + 84 + local number. From UK/Europe: 00 + 84 + local number. From mobile phones: +84 + local number.
Country calling codes are standardized by the International Telecommunication Union (ITU). The Vietnam country code +84 is used to route international telephone calls to Vietnam from any country in the world.