* Lion Air firms up order of jets worth $6.24 bln at list prices
* Had placed the provisional order for Boeing jets in June 2017
* Boeing 737 MAX 10 due to be certified by regulators in 2020 (Adds Boeing comments on delivery date)
JAKARTA, April 10 (Reuters) - Indonesian airline Lion Air Group on Tuesday announced a firm order for the purchase of 50 Boeing 737 MAX 10 jets worth $6.24 billion at list prices.
The rapidly expanding carrier had in June 2017 placed a provisional order for the jets, the newest and largest member of the Boeing narrow-body family.
Rusdi Kirana, co-founder of Lion Air, said the government's infrastructure expansion, which included airports, was fuelling Lion's demand for more aircraft.
Boeing Senior Vice President Asia Pacific and India Sales Dinesh Keskar said the Boeing 737 MAX 10 was due to be certified by regulators in 2020, with Lion Air expected to receive its first jets of the type soon after.
Boeing said it had been listing this deal as from an unidentified customer in its order book before Lion Air's confirmation.
Lion Air, one of Boeing's largest customers, was the first airline globally to take delivery of the smaller Boeing 737 MAX 9 earlier this year. (Reporting by Cindy Silviana and Bernadette Christina Munthe; Writing by Jamie Freed; Editing by Himani Sarkar)