For entry from all countries of the world, the following applies since Sunday, 1 May 2022:
ATTENTION: The EU COVID certificate for twice vaccinated persons is valid for 9 months for the purpose of entry into Italy.
Certificates must be in at least one of the following languages: Italian, English, French, Spanish or German. If the certificate was not issued in one of the five languages indicated, it must be accompanied by a certified translation.
If the person entering the country cannot produce a certificate stating that he or she has been fully vaccinated, recovered or tested, the following obligations apply:
There are still exemptions from the 3G obligation for certain categories (lorry drivers, crews of transport vehicles, etc.).
Information can be found on the website of the Italian Ministry of Foreign Affairs.