Italy is introducing a digital certificate for access to some services and venues in a bid to curb infections.
The "green pass" will allow access to people who have had at least one vaccine dose, have recovered from coronavirus or who have tested negative within 48 hours.
From Friday, anyone over 12 at venues such as gyms and restaurants must show their pass.
Italy is the second European country to require proof of status.
France has already introduced a health pass for access to restaurants, bars, planes and trains.
In Italy, customers and businesses that break the rules could face fines of up to €1,000 ($1,200; £850). Repeat offenders may be forced to close for 10 days.
Polls suggest the majority of Italians support the move, although it has been a source of protests in some parts of the country.
More than 60% of Italians have now been fully vaccinated. But infections have been rising driven by the Delta variant, with nearly 22,000 new cases reported so far this week.
Green pass requirements will be extended to university staff and all long-distance transport from 1 September.
However there are no plans yet to introduce green pass requirements in hotels, supermarkets and shopping centres.
Nightclubs meanwhile are to remain closed, despite suggestions by government ministers in recent weeks that they could reopen.
Other venues requiring a green pass for entry include bars, cinemas and museums. But people can avoid the green pass requirement at restaurants by eating outside.
The government has extended Italy's national state of emergency until 31 December.
Prime Minister Mario Draghi has also condemned right-wing politicians who have discouraged young people from being jabbed.
He said it was as "a call for people to die".