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.
“We believe this new connection will cater to both business and leisure travellers with direct, convenient and cost-effective flights between Belfast and Cardiff.”
