Air China has converted its order for 15 Boeing 787-8s to 787-9s, and expects to take delivery of the new aircraft from end-2015.
The 787-9 will be a better fit for the airline in terms of seat capacity, performance and economy, says China's flag carrier.
Air China placed its order for 15 787-8s in 2005 and had originally expected deliveries from mid-2008.
However, delays to the 787 programme since then have pushed back the first delivery to launch customer All Nippon Airways to the mid-first quarter of 2011.
Air China says it expects to take delivery of the 787-9s in stages from end-2015 to mid-2018.
The 15 aircraft have a list price of $3.2 billion before concessions, says Air China. The carrier said in September 2006 that it had chosen Rolls-Royce's Trent 1000 engines to power the 787s.
Air China estimates that the 15 787-9s will increase its fleet capacity by about 11% in available tonne kilometres.