What the international code for Luxembourg to call? Dial code number to open phone call in Luxembourg is ( 00352 ) or ( +352 ) in order to make international phone calls between Luxembourg and all countries of the world to unlock phone with more additional details and informations about Luxembourg country whereby each country is distinguished by a special telephone number, where the caller write the Grand Duchy of Luxembourg dial area code to opening sim card telephone line mobile or landline then the phone number.