Nok Air will start services between Bangkok and Betong, with three return flights a week, from March 14, the airline announced on Thursday.
Chief executive officer Wutthiphum Jurangkool said in a statement the low-cost airline would operate flights between Bangkok and the new southern airport in Yala province on Monday, Wednesday and Friday.
He gave no details of the airfare or the type of aircraft to be used on the new route.
Nok Air used a Q400 NextGen, an 86-seat twin-engined turboprop, on the first charter flight from Bangkok to the southernmost district of the country on Jan 29.
The start of services to Betong airport has been long delayed, with no clear explanation from transport or airport authorities.