How do you dial a number from India to Italy?

Italy is telephone country code +39. Landline numbers begin with +39 0; mobile numbers begin with +39 3. Note that Italy is an exception to the general rule that you drop the trunk prefix 0 from the beginning of the national number when calling internationally. For example, Rome's area code 06 becomes +39 06, not +39 6.

(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, and many other countries use different prefixes.)

The international access prefix from India is 00, so you dial 00 39 and then the Italian number (including the leading 0 for a landline).