Aegean Airlines has signed a memorandum of understanding for the purchase of 20 Airbus A320neos and 10 A321neos.
The Greek carrier will also acquire a "significant number" of new A320neo-family aircraft from leasing companies, Airbus says, in detailing the commitment.
Aegean in its own statement discloses that it will take options on 12 more of the aircraft.
The Athens-based airline, an existing Airbus narrowbody customer, disclosed in September 2017 that it was in the process of deciding whether to order Boeing 737 Max or Airbus A320neos as part of a refleeting programme.
Eftichios Vassilakis, the carrier's vice-chairman, states that the decision to pick Airbus over the Boeing 737 Max followed an "intense and exhaustive evaluation to determine the best aircraft for Aegean's growth and long-term success".
Aegean expects to complete the deal in June and says it will make an engine selection in July.
Flight Fleets Analyzer shows that the airline and its subsidiary Olympic Air have a combined fleet of 59 aircraft, comprising 37 A320s, eight A321s, 10 Bombardier Q400s, two ATR 42-600s, one A319 and one Learjet.
Source: Cirium Dashboard