Keep in mind Ireland is not part of Schengen, which means that when traveling from EU you do need a passport.
Unlike many international airports with many multiple terminals, the Dublin airport has two, aptly named Terminal 1 and Terminal 2.
Terminal 2, which opened in 2010, serves Aer Lingus, US carriers Delta, US Air, American Airlines, and United as well as Emirates and Norwegian. All other airlines, including Air Canada, will arrive in Terminal 1.
The following tips are specific to Terminal 2. If your flight arrives in Terminal 1 you will find it much the same, if a wee bit smaller. As Terminal 1 serves more European carriers there are far more EU immigration lanes, so visitors holding a non-EU passport may have longer wait times.
Bus and taxi transportation can be found at the lower level of both terminals, just follow the signs and join the queues, there is no need to prebook a taxi. If you are taking a bus into Dublin, splurge on the Aircoach. Clean and roomy, it costs only a few euro more than the other options and offers multiple drop-off points.
How to travel by train & ferry by The Man in Seat 61.
There are ferry routes run between Dublin and Holyhead in Wales and Douglas on the Isle of Man. Direct Ferries
The Luas tram system is the easiest way to travel around Dublin, once you work out the map. Buy a Leap Card, load it up with money, and tap to get on and off the tram.
Buses in Dublin are frequent, and you can use a Leap Card. Download the app for routes, timetables, and a real-time map.
There are plenty of bike stations in Dublin, and visitors can buy a three-day pass for unlimited journeys up to 30 minutes (extra rental charges apply after that). In the heart of the city, some cycle lanes are also tram lanes. Be careful when using these.
Use Uber or Free Now to order a car.