Phone numbers in Monaco are eight digits in length, with fixed line numbers beginning with the digit 9 and mobile phone numbers with the digit 4 .Until 21st June 1996, Monaco formed part of the French numbering plan, with fixed line numbers beginning with 93 , but in that year the principality adopted its own country code +377. Consequently, all calls between France and Monaco had to be dialled in international format, including those to and from surrounding areas in France. From Monaco to France : 00 33 x xx xx xx xx From France to Monaco : 00 377 xx xx xx xx