The airline is putting on four weekly flights, rising to five from 4 June.
The tickets are priced at £61 for a one-way trip and £99 for a return.
The head of the airline said that the new route would open up Cardiff to Islanders.
Christine Ourmières, CityJet’s Chief Executive Officer, said: “We are all very excited about our new route and hope that it will help to provide a vital connection for the people of Jersey to the Welsh capital.”
The Jersey-Cardiff route is the only service that CityJet is currently offering to Islanders. They run 650 flights per week, almost half of which operate through London City Airport.