What the international code for Czech Republic to call? Dial code number to open phone call in Czech Republic is ( 00420 ) or ( +420 ) in order to make international phone calls between Czech Republic and all countries of the world to unlock phone with more additional details and informations about Czech Republic country whereby each country is distinguished by a special telephone number, where the caller write the Czech Republic dial area code to opening sim card telephone line mobile or landline then the phone number.