The Dublin Airport Authority has revised its advice to passengers on security screening issues.
In recent weeks, there have been long queues at the airport.
Anyone due to fly from the airport to a short-haul destination in the EU or the UK in the coming days must arrive up to two and a half hours before departure time.
In a statement, the daa said: “Passengers flying short-haul flights departing after 08:30 are advised not to arrive at the airport before 06:00.”
For long-haul flights, it is recommended that passengers arrive up to three and a half hours before departure.
The daa said this will “relieve pressure on the passenger security screening area.”
Before going to the airport, passengers are advised to check with their airline when check-in and bag drop opens.
They are also encouraged to check in for their flight online when possible.
The daa said the new advice comes after security queue times improved from late March and over the Easter weekend.
He said the security check will remain open 24/7 at Terminal 1, with security open at Terminal 2 from 4 a.m.
Passenger tips will remain under review and “may be adjusted…either up or down as needed over the next period as the peak of the summer season approaches.”
The daa said around 200,000 passengers left Dublin airport over the Easter weekend.
It was the highest number of departures for four consecutive days since Christmas 2019.
It said no passengers missed their flight as a result of security delays, and “the vast majority of passengers” were processed through security “in less than 40 minutes at both terminals.”
According to the daa, it is in the process of hiring almost 300 new security control employees.