Flights from Western Canada/Calgary to Dublin

I think the easiest way will be to connect through Pearson ( Toronto) There are at least 3 airlines that go to Dublin from Pearson: Westjet, Air Canada and Aer lingus

Have you looked at Google flights or kayak? Kayak is showing many flights from Calgary to Dublin. Many with connections in LHR.

I’m flying home from Dublin this summer and chose AC Rouge to Vancouver and then the short hop home. To me, that’s much more bearable than a second long leg, another 4 hours home from Toronto. My first choice was Dublin-London, then the nonstop London-Calgary. Aer Lingus flies into the same terminal as Air Canada leaves from at Heathrow, so that looked easy. Couldn’t get a seat on Aeroplan points though, so ended up on Rouge Premium. Or Icelandair Dublin to Edmonton, WestJet or Red Arrow bus home. That one included a stopover in Iceland and was very inexpensive. If I hadn’t been trying to burn Aeroplan points, I'd have chosen that just for the fun of the stopover. Hope one of those works for you. I detest flying through Toronto or Montreal, it just takes longer overall and doesn’t have a nice long leg to try to get some sleep.

If you can't get a direct flight to Dublin then try connecting through Amsterdam instead of London. Heathrow is one of the worst designed airports I have been in, and any connecting flight seems to involve a lot of walking, possibly a bus ride, and then a lot of standing around. You need a minimum of two hours and I might suggest even more. Of course, if you can get a cheap flight from Calgary to Vancouver then a direct flight to Dublin that might be even easier. I think I flew Lufthansa direct to Dublin and it was fine.