Telephone 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 21 June 1996, Monaco formed part of the French numbering plan, with fixed line numbers beginning with 93, but on that date 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.
Monaco has its own international dialing code, the 377 on the 21st of June, at 21:00. Prior to this date, the Monegasque telephone was part of the french telephone network in the Nice Telecommunications Region and its telephone numbers were in conformity with the 8-digit French numbering plan AB PQ MC DU, the AB = 93 of which was allocated In the french department of Alpes-Maritimes, then including Monaco. Monegasque telephone numbers all started with AB = 93 until 21 June 1996.
At the technical level, the first automatic telephone switch of type R6 with recorders was installed in Monaco circa 1937-1938, the time of automation of the Cote d'Azur; And the inside Monegasque network followed the development of the French automatic telephone. We note the existence of an electronic time switch E10N1 in Monaco (Reference NC90), established before 1986 in Monaco by the PTT of France and who lived the transition of the PTT from France to Monaco Telecom in 1996.
From Monaco to France
x xx xx xx xx
From France to Monaco
xx xx xx xx
Mobile phone operators in at least two other countries, specifically Lonestar Cell in Liberia and Vala in Kosovo, also use the +377 dialing code.
Vala's use of +377 is due to cease on 15 December 2016, however, when Kosovo implements the +383 code.