SEOUL (Reuters) - Singapore Airlines will spend 1.1 billion Singapore dollars ($834.66 million) to upgrade all classes on its 41 Airbus A350-900 long-haul and ultra-long-range planes by the end of 2030, the airline said on Monday.

The airline group's SIA Engineering Company will carry out the retrofitting.

The first retrofitted A350-900 long-haul aircraft is expected to enter service in the second quarter of 2026, while the first A350-900ULR variant is expected in the first quarter of 2027, the airline said.

($1 = 1.3179 Singapore dollars)

(Writing by Lisa Barrington, Editing by Louise Heavens)