Rome FCO Transit Time

This is a frequently asked question and the answer is - it depends on many factors you cannot control. Biggest is on time arrival and immigration. However, at that time of night, immigration should be fairly quick. But sometimes the cut off for checkin is 45 minutes so you need to checked in by 9.35. Ryan air tends to be pretty strict. It could be tight. What are your options if you miss the 22.20?

PS I was aware that Ryan air used FCO.

I would not book that close. Budget airlines cut off check in well before the scheduled time of flight and are strict about it. With Easyjet it was 40 minutes; check to see what it is with Ryan. Are you sure they fly out of FCO; usually they fly out of the least convenient airport in a region. It is not unusual for planes to be late and it takes awhile to unload the plane and get to immigration which might go quickly or slowly and you can't control that (sometimes Roman agents will just wave people through -- don't let them do this as you need a record in your passport of when you arrived in Schengen and it can cause problems when you exit if you don't have it -- been there, done that) This scheduling only works if everything is perfect; any slight delay and you are likely to miss your flight. At that hour you are a bit less likely to be delayed long at immigration and security but it is still too tight unless you are comfortable with the idea of booking a new ticket for the next day. There is a Hilton at the airport but it is pricey.

Check your times carefully. 20:20 is actually 8:20pm not 10:20pm. Maybe you meant 22:20.
Also check the airport the RyanAir flight departs from. Nearly all RyanAir flights use Ciampino (CIA), only very few Ryanair flights depart from Fiumicino (FCO).
In the best of situation, this is very tight. You must have completed your checkin with Ryanair 45 min prior to departure before they close the flight. So just do your calculations. Flights are sometimes delayed too.

Thank you for all the feedback. I did make a mistake in my initial post. The departing Ryanair flight is scheduled for 22:20 (10:20pm) from Terminal 3, not 20:20 as I initially posted.
A couple comments suggested I double check the departing airport. I've checked on Kayak and eDreams web sites, and the FCO website. All indicate the Ryanair flight departing from FCO Terminal 3.
However it does seem there's a consensus that it will take a lot of good timing and luck to arrive at FCO, clear immigration, retrieve bags, clear customs, check-in, check bags, and race to the gate in about a 2 hour window from arrival.

Thank you all for the feedback and information.

I would only try it if I had a good back-up plan and didn't mind the potential cost increment . . . When is the next flight and if you have to buy a ticket on the spot, what are the chances it will have availability? Will you have to pay for the first night's hotel in Calabria if you don't show up? Where will you spend the night in Rome?

Realistically, you have to arrive at Ryan Air check-in by 21.20, leaving you one hour and 15 minutes to disembark, get to and through immigration, pick up luggage (customs is a walk-through), and get to Ryan Air. Then you may have to speed through the airport - remember, there's a security check - and to the gate before they close the flight. . . . and hope your checked luggage got on the flight. What could delay you? Any flight delay from Dubai, waiting on the tarmac for a gate, slow disembarkation, long line at immigration, delay in luggage offloading . . . .