What the international code for Liechtenstein to call? Dial code number to open phone call in Liechtenstein is ( 00423 ) or ( +423 ) in order to make international phone calls between Liechtenstein and all countries of the world to unlock phone with more additional details and informations about Liechtenstein country whereby each country is distinguished by a special telephone number, where the caller write the Principality of Liechtenstein dial area code to opening sim card telephone line mobile or landline then the phone number.