Virgin Australia has ordered 23 Boeing 737 Max 8 aircraft, with options for another four.
The aircraft will be delivered between 2019 and 2021, says the carrier in a statement on the Australian Securities Exchange.
It did not provide the financial details of the deal.
It adds that it will defer the delivery of an unspecified number of 737-800s to after 2016, and take only 31 between 2013 and 2016, to align with its capacity plan for the next three years.
Virgin has 47 737-800s that are scheduled to be delivered, according to Flightglobal Pro data. The airline receives an average of one a month, says a spokeswoman. She was unable to say how many aircraft will be deferred.
"This gives the airline flexibility to develop the appropriate mix of narrowbody and widebody aircraft," says Virgin Australia.
All eight Boeing 737-700s will also leave Virgin's fleet by the end of 2013, further reducing the average age of a fleet that came down to 4.2 years over the last year.
"The Boeing 737 has formed a critical part of Virgin Australia fleet over the past decade thanks to its reliability, comfort and fuel efficiency. The Boeing 737 Max will build on this, enabling us to achieve strong on time performance and maintain our low cost base," says its chief executive John Borghetti.
"Virgin Australia will continue to review its fleet strategy to ensure we align fit-for-purpose aircraft to markets and maintain maximum flexibility in capacity management."
Virgin operates a fleet of 737s, Boeing 777-300ERs, Airbus A330-200s, ATR 72-500s and -600s, and Embraer 190s.