The international dialing code for Tonga is +676. To call Tonga from the United States or Canada, dial 011 + 676 + area code + local number. From Europe, dial 00 + 676 + area code + local number. On mobile phones worldwide, use +676 followed by the area code and local number.
From USA/Canada: 011 + 676 + local number. From UK/Europe: 00 + 676 + local number. From mobile phones: +676 + local number.
Country calling codes are standardized by the International Telecommunication Union (ITU). The Tonga country code +676 is used to route international telephone calls to Tonga from any country in the world.