Go through the entry questionnaire here
infocovid.viaggiaresicuri.it/returningtoitaly.html
And you get
“In accordance with Order of July 29, 2021 and Order of August 28, 2021 adopted by the Minister of Health, in force until October 25, 2021, the United Kingdom of Great Britain and Northern Ireland (including Gibraltar, the Isle of Man, Channel Islands and British bases on the island of Cyprus) falls into List D (click on the blue button on top of the page for the complete Lists of Countries and Territories).
Travellers coming from the UK or who have visited/transited the UK in the previous fourteen (14) days, must:
fill out a digital Passenger Locator Form (only in case of lack of necessary tools to fill out the dPLF, you can use a paper-based self-declaration) and present it to the carrier or any other authorised person, either printed or on one's mobile device.
present to the carrier, or any other authorised person, a certificate of vaccination stating that the cycle of vaccination has been completed with an EMA-athorised vaccine or a EU Green Pass proving the same;
take a molecular or antigenic test, carried out by means of a swab and with negative result, in the 48 hours before they arrive.
In case of lack of the certifications under points 2 and 3 (which are not alternative), travellers may still enter Italy but they must:
self-isolate for five (5) days, activating local health surveillance procedures by informing Local Health Authorities.
get tested again, upon completing the prescribed self-isolation.
Border Officers in Italy may always request that you fill out a paper-based self-statement upon arrival.
ENTRY OF MINORS
In addition to cases of exemption already mentioned in the relevant paragraph:
Molecular or antigenic test
Children from 0 to 5 years of age do not have to undergo a molecular or antigenic test.
From 6 up to 17 years of age: the test is mandatory, if requested according to the relevant rules depending on the history of travel in the 14 days prior to entering Italy.
Self-isolation
From 0 to 17 years of age, minors are exempt from the requirement of self-isolation if they are accompanied by a parent who is also exempt from such requirement because of the possession of a certificate of vaccination (or a certificate of recovery, if applicable based on the history of travel in the previous 14 days).
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