Calling San Marino from the United States explained:

• 011 - US exit code; dial first for international calls made from the USA or Canada
• 378 - Country Code for San Marino
• Phone Number - 10 digits
• US to San Marino landlines international dialing format: 011 378 0549 ??? ???

How to dial to San Marino cellular:

• dialing format for calls to a cell phone: 011 378 3?? ??? ???? (or 6?? ??? ????)

Phone Books:

• Pagine Gialle - Italian Yellow Pages, includes San Marino
• Pagine Gialle and Pagine Bianche - Yellow Pages and White Pages respectively, in Italian