SriLankan Airlines is to order seven Airbus A350-900s and six A330-300s.
It is to purchase 10 of the aircraft - four A350s and the six A330s - and will lease the other three A350s.
SriLankan chief executive Kapila Chandrasena says the discussions on the lease arrangement have yet to conclude.
Airbus values the agreement at $2.6 billion at list prices.
Rolls-Royce says SriLankan has selected Trent 700 engines for the A330s while the A350s will be fitted with Trent XWBs, the only powerplant currently available.
"This transaction is to replace the widebodies," says Chandrasena. SriLankan's fleet of 21 aircraft includes 13 long-haul jets, six A340-300s and seven A330-200s.
"Over the next 10 years we'll be replacing those," Chandrasena adds. SriLankan taking the A330-300s from October 2014 and the A350-900s from 2017.
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