EVA Air has signed a letter of intent to purchase up to 24 B787-10s and two B777-300ERs from Boeing.
The deal is valued at more than US$8 billion at current list prices. Once finalised, it will represent the Star Alliance member's first foray into the Dreamliner market.
The B787-10 is the largest variant of Boeing's 787 family, and will position EVA Air alongside launch carrier Singapore Airlines, Etihad Airways and United Airlines.
The aircraft will also allow EVA Air to progressively retire its older aircraft. Specifically, the carrier still operates nine A330-200s and these are expected to be replaced by newer aircraft in the coming years.
EVA Air is also looking to strengthen its B777-300ER fleet, by adding two more aircraft to its growing list of orders for that model. It currently has 21 B777-300ERs, making it the world's eighth largest operator of the aircraft and the fourth largest in Asia.
Ray Conner, Boeing's commercial airplanes president and chief executive, said: "We look forward to welcoming EVA Airways as Boeing's newest member of the 787-10 Dreamliner launch customer group."