The last time the national carrier flew from the capital to the two resort provinces was April 1.
There will be three flights a week - on Fridays, Saturdays and Sundays - on both routes and the new schedules will run until Feb 28, the source said.
He added that the flights would operate with the wide-bodied Boeing 777-200ER aircraft, with a full onboard service on offer and miles being earned by Royal Orchid Plus members.
The resumption of domestic flights follows the airline’s announcement last month that it would be relaunching scheduled international flights from Jan 1 to March 27.
It will fly one flight every Friday to Frankfurt and London, and a Sunday flight to Copenhagen and Sydney. THAI will also fly one Wednesday flight to Seoul, a Thursday flight to Manila, one to Taipei on Fridays and one to Osaka on Saturdays.
Bangkok-Tokyo flights will be available three times a week - on Monday, Wednesday and Saturday - while the Bangkok-Hong Kong flights will be available every day.
The airline is seeking to make up losses worth more than B300 billion in the Central Bankruptcy Court.
Meanwhile, Somdet Susomboon, director-general of the Department of International Trade Promotion, says THAI will support exporting Thai fruit and vegetables to Asia and Europe until the end of next year under an agreement between the Commerce Ministry, the Agriculture and Cooperative Ministry and the Transport Ministry.
Mr Somdet said the major markets for Thai produce were Hong Kong, South Korea, Japan and Europe.
Meanwhile, Pattaya mayor Sonthaya Khunpluem says the seaside town’s Fireworks Festival on Nov 27-28 was a huge success, attracted between 100,000-200,000 visitors a day, boosting local tourism and resulting in 100% hotel occupancy rate.
Mr Sonthaya estimated that during the two-day festival, about B2,000 was spent by each person per day, generating more than B400 million.