Ryanair is due to start 13 new routes to eight countries, including Dublin, Alicante, Barcelona Reus, Bilbao, Brest, Corfu, Cluj, Faro, Kosice, Malaga, Milan Bergamo, Palma and Venice in April.
Ryanair today said it will open a new base at London Southend from April 2019.
Ryanair is opening a new base in Britain - in an apparent U-turn after warning that Brexit would be a disaster for the United Kingdom and the country's airline industry.
Nevertheless, the Ryanair deal is a significant coup for Stobart, whose aviation unit also operates the Aer Lingus Regional service on a franchise basis.
Stobart has been pushing hard to develop London Southend Airport as a viable alternative to other airports around the United Kingdom capital, including Stansted, which is Ryanair's largest base.
Ryanair will begin operating flights from London Southend Airport next year, it has announced.
Last year, Stobart, whose CEO is former EasyJet executive Warwick Brady, said it hoped to handle 2.5 million passengers at Southend in 2018.
More than 55 flights a week will see Ryanair carry an estimated one million passengers per year. "We have a clear and focused strategy to grow our airport to welcome over 5 million passengers a year by 2022", he said. In recent weeks he has demanded chairman Iain Ferguson steps down.