Japan Airlines has ordered 10 Boeing 787-9s and converted orders for 10 787-8s into the -9 model.
The airline also has options for 10 more 787-9s as part of the latest deal, it said in a statement. With this, JAL has 25 firm orders for the 787-8 and 20 for the 787-9, with 20 options for both types.
The airline plans to deploy the 787-9s on medium to long haul international routes after the 2015 fiscal year, which ends on 31 March 2016.
The aircraft will help it to significantly bring down its operating costs, and allow it to take advantage of the additional slots at Tokyo's Narita and Haneda airports.
JAL had been due to take delivery of its first 787-8 around end-February, but it said earlier this month that this had been indefinitely delayed.