What the international code for United kingdom to call? Dial code number to open phone call in United kingdom is ( 0044 ) or ( +44 ) in order to make international phone calls between United kingdom and all countries of the world to unlock phone with more additional details and informations about United kingdom country whereby each country is distinguished by a special telephone number, where the caller write the United Kingdom of Great Britain & Northern Ireland dial area code to opening sim card telephone line mobile or landline then the phone number.