New destinations will include Manchester, Dublin, Nantes, Cologne, Copenhagen, Mykonos and Valencia.
Passengers can now book seats for the new routes, with Ryanair offering a sale for seats from €24.99, for travel in April 2019, which must be booked by midnight Monday (Oct 1) via its own website.
Each airport will have two new aircraft (four new planes in total), representing an investment of $400m (€344m).
The new bases will offer 27 new all-year flight routes, rising to 64 over summer 2019.
Ryanair estimates that they will serve a total of 3.5 million customers per year, within the next three to four years.
Marseille will be the bigger operation, with 150 weekly flights, four million customers per year, and 40 routes for summer. It will also create 60 new Ryanair jobs, and 1,800 other on-site jobs.
Destinations from Marseille will include Manchester, Agadir, Alicante, Bologna, Bucharest, Budapest, Naples, Prague and Warsaw.
This is the first time that Ryanair will have a hub in Marseille, after its most recent operation there closed in 2011.
Bordeaux - an entirely new hub - will offer 70 weekly flights, to 1.1 million annual customers, and 24 new routes for summer. It will offer 60 new Ryanair jobs, and 825 on-site roles.
Destinations from Bordeaux will include Manchester, Nantes, Bari, Cologne, Copenhagen, Dublin, Fez, Krakow, Marrakesh, Mykonos, Naples, Tangier, Valencia and Venice.
Ryanair will also fly daily between the two airports themselves.
In a statement on the Ryanair website, Pascal Personne, Chairman of the Executive Board of Bordeaux-Mérignac Airport, said: “Ryanair’s decision to base two aircraft at Bordeaux is excellent news for the airport and for our region.
“This new base will undeniably increase the attractivity of Nouvelle-Aquitaine and represents the opportunity to develop a large number of new destinations. We have been actively working with Ryanair since 2009 and we believe that [this] is very important for Bordeaux and is a sign of a long-term commitment.”
Philippe Bernand, Chairman of the Executive Board of Marseille Provence Airport, said: “We are very pleased with Ryanair’s decision to accelerate its development in Marseille.
“It is an essential and historical partner of our airport, and more generally of our country, from a tourist and economic point of view.”
The announcement marks the second time this week that Ryanair has hit headlines.
Today (Friday September 28) it has cancelled over 190 flights across Europe due to ongoing strikes from staff, which it has called “unjustified”.
It blamed the cancellations on “a small minority of staff”, yet warned that continued strikes could make 2019 a difficult year.
In a statement this week, Ryanair marketing director Kenny Jacobs said: “These repeated unnecessary strikes are damaging Ryanair’s business and our customer confidence at a time when oil prices are rising strongly.
"If [strikes] continue, it is inevitable that we will have to look again at our capacity growth this winter and in summer 2019.”
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