Matt Damon of course spent a lot of the lockdown for COVID-19 here in Ireland at Killiney and went swimming at the Forty Foot in nearby Sandycove.
It is possible to visit the castle despite COVID-19 restrictions but due to filming schedules, set-up etc. for the next few weeks Cahir Castle is closed to the public. Filming finished in early October 2020 and moved to Bective Abbey.
A walkthrough of Cahir Castle where filming for The Last Duel has been taking place.