(Review by ) Well Dublin airport is hard to sum up, but easy enough to sleep. You won’t be stopped from sleeping unless by cleaners. I’ve seen airport police watching over sleepers at night to make sure they are ok. Best part was free, fast and unlimited wifi! Terminal 1 landside has good sleeping spots up in beside mcdonalds but these seats usually fill up fast. Security opens at 3.30 am for Terminal 1. Terminal 2 has good sleeping spots beside restaurants, but not as comfy as terminal 1. Security opens up at 4am. My recommend the following. Try to find a sleeping spot in the restaurants and then try to be at T1 security (5 minutes walk away from terminal 2) at 3.30am to go through.
There are good couches and sleeping spots down at the 301-307 gates, 333-335 gates and at the end of the duty free for terminal 1 airside. For Terminal 2 you can get there from terminal 1 security and walk 5 minutes to terminal 2 by following the 400 gates signs. My secret find and secret room I found in terminal 2 was beside the escalator at gate 407 and 408. Beside the water fountain and the escalator (there’s a small and tall one) there’s a room called PRM room. If you need for help look for the lifts to USBCP in terminal 2 beside the big american flag and it is the room beside the lifts. Inside it there’s an empty room with some of the nicest couches you’ll find for free, airport staff usually sleep here! Great quiet spot for a sleep. Gates are hidden on the screens until 45 minutes before the flight. However, if you go down to the gates themselves usually the screens display the gate numbers.