What the international code for Montserrat to call? Dial code number to open phone call in Montserrat is ( 001664 ) or ( +1664 ) in order to make international phone calls between Montserrat and all countries of the world to unlock phone with more additional details and informations about Montserrat country whereby each country is distinguished by a special telephone number, where the caller write the Montserrat dial area code to opening sim card telephone line mobile or landline then the phone number.