Originally Posted by
pvrMM3
As of 5/1 Delta and other Skyteam pax no longer have access to the ITA lounges.
The Hello Sky lounge is the only lounge I know of for International Arrivals in Rome. It's on the way to the trains and signs in English say something like Arrival Lounge and Day Rooms. As far as I know that will be your best bet. I haven't gone in it, but I have walked by it many times. I have no clue on access.
Here is their website --
https://hellosky.travel/services/lounge/
I went through the booking page and it quoted 25 Euros for 3 hours of access.