The tours will be available to passengers with layovers of six to eight hours. Tourism Authority of Thailand governor Thapanee Kiatphaibool said Suvarnabhumi alone handles about 1.3 million transit passengers a year, and the agency is aiming to pull roughly 10% of them into the program.

Three types of tours are planned. One covers cultural and historical sites, including the Grand Palace and the Temple of the Emerald Buddha. Another centers on Thai food, taking visitors through street food and local cuisine. A third offers health and wellness packages built around spa treatments and traditional Thai massage.

Thailand ranks as the second-largest aviation market in Southeast Asia by seat capacity, behind Indonesia. The free-tour plan is meant to capitalize on that position, converting passengers who would otherwise wait out a layover inside the terminal into same-day visitors who spend money in the country and reinforcing Thailand's role as a regional transport hub.

The approach mirrors one already running in Hong Kong, where Hong Kong International Airport offers free city tours to passengers with layovers longer than seven hours. That program has targeted 5.5 million passengers a year.