British Airways stablemate Aer Lingus will operate the new route daily using an Airbus A320 aircraft. Flights will depart Knock at 1.05pm and arrive into Heathrow at 2.30pm. The inaugural service took off on Sunday afternoon (26 March).
Aer Lingus said the new link would allow travellers in the west of Ireland to take advantage of worldwide onward connections from Heathrow.
Knock, meanwhile, serves as a gateway for UK travellers to the Wild Atlantic Way, placed in the spotlight in recent months by Oscar-nominated film The Banshees of Inisherin.
