Telephone numbers in San Marino consists of ten digits, starting with the digits 0549. Calls within Italy, Vatican City and San Marino are always dialled including all digits, including the leading zero.
Until 1996, San Marino was part of the Italian telephone numbering plan, using the Italian area code 0549 but in that year it adopted its own country code 378. However, instead of using international dialing codes, dialing arrangements between San Marino and Italy continued as before. In 1998, as Italy switched to a closed dialling plan, San Marino incorporated the 0549 area code into its subscribers' numbers, following the Italian format:
0549 xxx xxx (San Marino from Italy)
+378 0549 xxx xxx (San Marino from rest of the world)
+39 0549 xxx xxx (San Marino via Italy)