The Department of Transport has awarded Aer Arann the Knock-Dublin public service obligation (PSO) route.
There is currently no service on the route as CityJet pulled out, having won the tender earlier this year. Aer Arann had operated the route until July.
Aer Arann will provide a daily early morning service from Knock to Dublin and an evening return service, beginning on October 1.
Aer Arann already provides services on the PSO routes linking Dublin with the regional airports in Galway, Derry, Sligo and Donegal, while Ryanair provides the Kerry PSO service.