What the international code for Guernsey to call? Dial code number to open phone call in Guernsey is ( 000 ) or ( +0 ) in order to make international phone calls between Guernsey and all countries of the world to unlock phone with more additional details and informations about Guernsey country whereby each country is distinguished by a special telephone number, where the caller write the Bailiwick of Guernsey dial area code to opening sim card telephone line mobile or landline then the phone number.