Originally Posted by NotHamSarnie

It's 30 min to last-chance check-in. You have to do this in person as there are security questions i.e., you can't just go to the gate. I typically arrive at T2 in DUB at least 2 hours in advance, and this is as someone traveling in J (Sky+ checkin, fast-track through DUB security, J through secondary security) and with GE (passport/customs) and no checked luggage i.e., the very quickest one can do. Your parents have zero chance there. There will be queues through passport control in T1, pickup of luggage, transfer to T2, queues to check in, queues through DUB security, queues through 2ndary security, queues through passport/customs.