Calling Monaco from the United States explained:

• 011 - US exit code; dial first for international calls made from the USA or Canada
• 377 - Country Code for Monaco
• Phone Number - 8 to 9 digits
• US to Monaco international dialing format: 011 377 ???? ????

How to dial to Monaco cellular:

• dialing format for calls to a cell phone: 011 377 X??? ????(?)
• the leading digit X can be 3, 4 or 6

Phone Books:

• Pages Jaunes - White and Yellow Pages, in French
• Monaco Business Directory