Getting from Belfast to Dublin by bus

Yes, but it's a good idea to prebook. We took the bus from Dublin airport to Belfast, and we took the bus from Belfast to Dublin (city not airport). On the bus from Dublin, people who had not prebooked were not able to get on the bus, as it was full.

Thank you BB for the hot tip! Any idea where you prebook? If not I’m sure I can figure it out! Many thanks!

From translink- the Northern Ireland transport authority-
https://www.translink.co.uk/

It is not as intuitive as it could be. First select your journey, then on the right hand side of the page 'buy online'.
On the next page, click the '+' button on the left hand side, then choose the number of passengers and duration, then 'confirm' then click the radio button next to your chosen departure, finally 'Buy Now' on the right hand side of the page.

Another service is Aircoach. I took this from Belfast to DUB last spring, quick and easy. Booking ahead would be a very good idea. A few days ahead was enough for me last May.

May I ask a related question to this thread? We are planning to go from Central Dublin to Belfast International Airport to pick up a rental car for the NI part of our trip. If I understand right, we need to take a bus into Belfast and then another bus out to the Belfast International Airport. So what is the best bus company and bus stops to get on and off. Thanks in advance.

If you use the Translink service above you can book a through ticket to Belfast International - change at Belfast Europa Bus Station (the final stop coming from Dublin), bus every 20 minutes off peak /5 minutes peak Europa to the Airport.
Service from Dub to Belfast Europa hourly.

But every two hours the Aircoach to Derry/Londonderry runs through (without change) from Central Dublin to Belfast International.

So it's all personal choice

Great information! Thank you very much!

Also, do you think buying a ticket a couple days in advance is early enough?

oanncope: Is there an overriding reason why you want to go all the way out to the international airport to collect your car?
There are several rental car outlets within walking distance of the train station and, alternatively, there are a number located at the George Best city airport just a mile or two up the street.

It's effectively a walk up and go coach service, so 2 days beforehand is ample.

PS- George Best airport has another shuttle bus and it's own train station.

The reason we are going to the International airport to pick up the car is because at the time we made the rental reservation, we were told it would be easier to drive out of that airport to our destination up north than drive through Belfast and out of town. We are not young and prefer to keep the driving as simple as possible. Thanks to everyone for their responses. I'm sure I'll have more bus questions later about other towns. Appreciate your patience. I do try to look online for answers but the people on this forum seem to explain it easier. Thanks again!
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Thanks for the information on pre-booking. Does anyone have experience getting through immigration and customs and how long it takes. We arrive from the US via Air Lingus. Arrival is in the AM. Trying to decide if I book a bus for 2 hours after arrival is reasonable or should it be longer?

We arrived in Dublin 7 days ago. We flew Aer Lingus from Newark and arrived at 4:45 in the morning. It’s a bit of a walk from the arrival gate to passport control. There were no lines and we breezed through. Follow the signs for buse”transportation. You can take the Air Coach bus directly into Dublin. At the pickup site there are signs indicating bus numbers and routes. You can pay with cash or credit card. If you’re going directly to Belfast prebook you ticket on the Aircoach website. It’s easy to do. The trip is about two hours and will bring you to the bus station in Belfast. This is where you can get another bus to the international airport. Other people are correct. The bus to Belfast does fill and passengers are turned away. If you miss you’re bus you can use your ticket on the next bus. It’s an easy system to use and people are helpful and friendly. You’ll love Northern Ireland.

Thanks so much for the information.

For everyones reference translink are the public transport provider in Northern Ireland...there is no other public transport provider except them ... aircoach are a private company ...to get to Belfast international airport take the 300 Ulsterbus service to the airport from Europa bus station which is the same bus station that the X1 bus from Dublin airport comes into www.translink.co.uk

If your trip begins at Dublin Airport, you book through Aircoach, even if you are booking round trip. If your trip begins in the Northern Ireland, or you book your return trip to Dublin separately, you need to book through Translink.

If your trip begins at Dublin Airport, you book through Aircoach, even if you are booking round trip. If your trip begins in the North of Ireland, or you book your return trip to Dublin separately, you need to book through Translink.

Not so. As stated by Paul translink and aircoach are two different competing operators. If you wish to travel on the Translink bus in either direction (to or from Dublin) or return you book on the translink website, and pay in £ sterling, if you wish to travel on aircoach you book on their website.
Time was when the translink service was a "code share" with Bus Eireann (the Irish, formerly state, but now privatised operator- the equivalent of National Express in the UK) and journeys from the Republic had to be booked via Bus Eireann but those days are long gone.
AirCoach are the equivalent of Megabus or Flixbus in the UK.

Well, that’s what I had to do last May. Perhaps it has changed.

I just traveled to Belfast from Dublin Airport in early June. I booked through Aircoach. I booked multiple transfers - Dublin Airport to Belfast, Belfast to Galway by way of Dublin Airport, then back to Dublin Airport from City Center (we opted to take the train from Galway to Dublin just to get a variety of transportation experiences). I found Aircoach to be very comfortable, reliable, and easy to book. Booked everything at once on the same site. I even got a discount for multiple bookings.