What the international code for Holy See Vatican City State to call? Dial code number to open phone call in Holy See Vatican City State is ( 0039 ) or ( +39 ) in order to make international phone calls between Holy See Vatican City State and all countries of the world to unlock phone with more additional details and informations about Holy See Vatican City State country whereby each country is distinguished by a special telephone number, where the caller write the Holy See Vatican City State dial area code to opening sim card telephone line mobile or landline then the phone number.