The contracts, negotiated earlier in the year, were signed yesterday to coincide with the visit to Seoul by French President Francois Hollande.
South Korea's largest carrier, Korean Air, signed up for 30 Airbus A321neo planes, worth around USD 3.7 billion at list prices. It also took options on 20 more of the aircraft.
The second biggest carrier Asiana contracted for the delivery of 25 A321neos, with a catalogue price of around USD 3.1 billion.
"South Korea is an increasingly large and important market for us," said Airbus CEO Fabrice Bregier, who was part of a business delegation accompanying Hollande on his visit.
"It's a large domestic market but a sizeable transport hub for the rest of Asia," Bregier said.