Acting vice-president Surapol Isarakura na Ayutthaya said on Friday the Sendai route is one of several services to be cancelled. He did not name the other routes, but said the changes will occur in the last quarter of this year.
THAI has operated three flights a week to Sendai since Dec 30 last year. The Japanese city is one of its seven destinations in Japan, including two airports in Tokyo.
The airline will increase flights on popular routes in China, Japan, Scandinavia and Pakistan, Mr Surapol said.
He said THAI expected to report a 10 billion baht loss this year, down from 12 billion baht a year ago.
With the total loss in the first half already 10 billion baht, the national carrier was banking on an increase in passengers and income in the last four months of the year, he added.
THAI suffered from poor management and its poor performance was made worse by the political unrest that ended with the military coup on May 22.
Passenger numbers were expected to improve to 70% capacity from next month tthrough o the end of the year, up from 60%, the vice president said.
THAI will hold talks with THAI Smile and Nok Air next week to map out a plan to compete with other budget carries based at Don Mueang airport.
THAI Smile, the subsidiary of THAI, relocated some flights to Don Mueang from Suvarranbhumi airport on Friday. It flies three flights between Don Mueang and Chiang Mai, three flights between Don Mueang and Khon Kaen and two flights between Don Mueang and Phuket.
The rest are planned to move to Don Mueang in October.
Thai AirAsia and Nok Air dominate the low-cost service at Don Mueang.
THAI is a major shareholder of Nok Air.