The international dialing code for Monaco is +377. To call Monaco from the United States or Canada, dial 011 + 377 + area code + local number. From Europe, dial 00 + 377 + area code + local number. On mobile phones worldwide, use +377 followed by the area code and local number.
From USA/Canada: 011 + 377 + local number. From UK/Europe: 00 + 377 + local number. From mobile phones: +377 + local number.
Country calling codes are standardized by the International Telecommunication Union (ITU). The Monaco country code +377 is used to route international telephone calls to Monaco from any country in the world.