Dublin Airport is about ten kilometres north of the city centre and there is no rail connection — the long-promised metro link has been in planning for over two decades and is not built. Everything into the city goes by road, which means journey times depend on traffic.
Budget 30 minutes off-peak and up to an hour at rush hour, in either direction.
The options
Airlink Express (747) — the dedicated airport bus, running to O’Connell Street, Bachelors Walk and Heuston Station. Frequent, luggage racks, about 30 to 45 minutes. Covered by the Leap Visitor Card, which is why that card usually pays for itself on a short trip.
Aircoach — a private operator with several routes, including one that runs south to Ballsbridge, Donnybrook and Leopardstown, and one to the city centre. Useful specifically if you are staying on the south side, because it saves a change. Runs 24 hours on the main routes.
Dublin Bus routes 16 and 41 — ordinary city buses that happen to serve the airport. Much cheaper than the Airlink, slower, and with no luggage space to speak of. The 41 goes to Lower Abbey Street; the 16 runs through the centre and out to Rathfarnham. Perfectly reasonable with a small bag and a poor idea with two suitcases.
Taxi — metered, about 25 to 40 minutes off-peak, and considerably more in traffic. There is a marked rank outside each terminal with a queue that moves. Roughly the cost of four bus fares for two people, which makes it defensible if there are two or three of you.
Ride-hailing — Uber operates in Ireland but only dispatches licensed taxis, so it is not cheaper than the rank, just app-based. FreeNow is the app most locals use.
Which to take
Staying in the city centre, travelling light: the Airlink, or the 41 if you want the cheapest.
Staying on the south side — Ballsbridge, Donnybrook: Aircoach, and skip the change.
Arriving late at night, or with children and luggage: taxi. The buses run late but the walk from the stop with bags at midnight is the part people underestimate.
Two or more people: compare properly. A taxi split two ways is close to the bus fare and drops you at the door.
The two terminals
Terminal 1 — Ryanair, Aer Lingus short-haul and most European carriers. Terminal 2 — Aer Lingus long-haul, and most transatlantic and long-haul airlines.
They are a five-minute walk apart along a covered walkway. Buses serve both; check which stop you need, because they are on different sides.
US preclearance
Dublin is one of a handful of airports outside the Americas with US Customs and Border Protection preclearance. If you are flying to the United States you clear US immigration and customs in Dublin, and land in the US as a domestic arrival — no queue at the far end, and you can connect onward to domestic flights without re-checking bags.
The practical consequence: allow substantially more time at Dublin than you would for a normal international departure. Airlines recommend arriving around three hours before a US flight and it is not padding — preclearance is a full immigration and security process and the queue at 7am can be long.
Practical
No rail link, and no realistic prospect of one soon. Ignore anything that mentions the metro.
Leap Visitor Card covers Airlink, Dublin Bus, Luas and DART, and can be bought in the arrivals hall.
Luggage storage is available at the airport and at several places in the city centre if you have a late flight and an early checkout.
Coming back: allow for traffic. The M50 and the Port Tunnel approach both back up badly in the evening peak, and the bus is stuck in the same traffic as the taxi.
Arriving from the UK
Ireland and the UK share the Common Travel Area, so there are no routine passport controls on flights between them — but airlines require photographic ID, and most insist on a passport regardless of the legal position. Bring one.
Ireland is not in the Schengen Area, so an Irish stamp does not consume Schengen days, and a Schengen visa does not admit you to Ireland. Check your own nationality’s requirement for both separately if your trip covers the continent as well.
Money
Ireland uses the euro. Northern Ireland, an hour and a half up the road, uses sterling — which catches people out on a Belfast day trip.
Card acceptance is close to universal, including on the Luas and DART. Cash is still needed for some buses and the odd old pub.
The other airports
Belfast International and Belfast City are two hours north by road and are occasionally much cheaper on a UK routing. The Enterprise train and the Aircoach both connect, and remember the currency changes.
Shannon, in the west, is a two-and-a-half-hour bus and is worth checking for transatlantic fares if you are touring the country rather than staying in the city.