Where is telephone country code 378?

Answer 1

Country code +378 (dialed as 00 378 from many places) is the Most Serene Republic of San Marino, a tiny republic completely surrounded by Italy.

Note that all landline telephone numbers in San Marino begin with +378 0549, followed by 6 further digits. Calls to and from Italy can be dialed with just the 10-digit national number. As with Italy, you do not drop the leading 0 of the national number in international format.

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)