Aer Lingus Regional will operate four times a week between Belfast City airport and Cardiff from 28 June, while Dublin-Cardiff will commence on 30 August, initially three times a week.
Flights will be operated for the Irish carrier by Stobart Air.
One way fares between Dublin and Cardiff will be from £36.99, with Belfast-Cardiff from £29.99.
Stobart managing director Andy Jolly said: “Anticipating a successful Covid-19 vaccination rollout which will allow air travel to resume safely later this year, we are pleased to add this route from Belfast to Cardiff to our network.
