The Welsh Government, which controversially bought Cardiff Airport last year for £52m after years of declining passenger numbers, says Ryanair's return "is proof that the airport is a highly attractive proposition for airlines."
Last month, the airport announced a 9 per cent increase in passenger numbers since being taken over by the Welsh Government.
Last year, Thomson, First Choice and Lufthansa all announced extra flights.
This January, CityJet stepped in to run services to Paris and Glasgow, after Flybe withdrew.
Cardiff Airport has said it is "delighted" that airline Ryanair has decided to begin flying again from the Vale of Glamorgan base, and it is "a major opportunity to increase choice for our customers."
Ryanair is returning to Cardiff, after withdrawing its route to Dublin in 2006.
Low-cost airline Ryanair has announced it will return to Cardiff Airport later this year with a new route to Tenerife.
The new weekly service to and from the destination will start from 30 October and the airline hopes it will take around 15,000 passengers each year.