Are Dolphins really that common around the north coast and have you ever seen any?

I always wanted to go whale and dolphin watching but I didn't think Northern Ireland would be a good spot for it but I was reading about this topic online and I saw a bunch of videos of Dolphins, porpoises and even killer whales in Northern Ireland.

Alot of the videos seem to be around the North coast from Ballycastle to Lough Foyle direction, I really like nature but I've been around the north coast alot and have never been lucky enough to see any dolphins or anything.

I was wondering has anyone in this sub ever seen any in the wild and what was the experience like seeing such cool animals?