Oops - Typo in original post Airport and train station transfers

You could take the bus to Knock and get RyanAir to Edinburgh (if the day is right), then the Megabus from EDI to Glasgow? Ignore this idea if I misunderstood what you're trying to do.

Galway to Knock to EDI to GLA seems a very roundabout route. The Galway to Knock airport bus takes 1 3/4 hours, and runs every 2 hours then 1 hour back from EDI to GLA on Scottish Citylink

On the Edinburgh to Glasgow the bus is a codeshare, but is run by Citylink (very rarely will it be in Megabus livery), and is as cheap booked with Citylink.

Far more sensible to take the 24/7 bus of any of three companies direct to Dublin Airport. Almost as fast as going to Knock. Aer Lingus and Ryanair both fly the Dublin to Glasgow route with multiple flights daily.

Unless you have a burning wish to take the train, bus is the better alternative, although there is a dedicated express bus route (with on board luggage racks) direct from Heuston station to the airport. No need at all to take a taxi

I've flown the DUB-GLA route a few times. Very easy. (Aer Lingus.)

Take the bus directly to the airport. The train is okay and a taxi from the train station to the airport isn't bad but will be more than for two on the bus. (If it was four I'd definitely recommend a taxi.) The intercity buses in Ireland, IMHO, are more comfortable than the trains.

FYI--when you arrive in GLA there will be no immigration or customs. When you enter Ireland you will also be given permission to enter the UK. (But not vice versa.)

So sorry - I confused things a bit. Not really a typo - just confusion by my sentence structure perhaps. My thanks to those who replied.

I did not mean to inquire about getting from Dublin to Glasgow. We plan to fly for that leg. I just meant to ask about transport between Galway and Dublin.

This is the Galway to Dublin train timetable- https://www.irishrail.ie/getmedia/81529cec-6419-43db-9b2d-4563775766e6/06-Dublin-Galway.pdf

And this is the #782 bus Heuston to Dublin Airport

And Galway to Dublin Bus 1-Aircoach 706X- https://www.aircoach.ie/timetables/706%20706X/pdf?date=2022-12-27&day=

2-Citylink-https://www.citylink.ie/timetables/galway-dublin

3-GoBus 720- https://ticketbooking.gobus.ie/timetable/timetablehome

Our taxi from then Heuston station to our hotel at the Dublin airport was approximately €30…this was mid September, two of us with carryons and backpacks. There is a taxi queue just outside the station.

Many thanks for all the helpful information.