Industry insiders said heavy smog has become the major driver of winter travel.
The online travel agency Ctrip said on Monday that it expected to send more than 150,000 travelers to overseas destinations in December, simply to escape the smog.
UTour International Travel Service Co didn't give specific figures, but it said the number of travelers in December has increased by 10% to 15% compared with last year, and smog is the major cause.
Travel agencies including UTour, Lvmama and Ctrip said Beijing, Tianjin and Hebei still account for the largest number of tourists who want to escape smog.
Domestic tourism destinations that offer a good natural environment and air quality are the beneficiaries, including Sanya in Hainan and Lijiang in Yunnan. Overseas destinations with loosened visa policies also are drawing many Chinese tourists.
Additionally, many lesser-known tourism destinations, such as Xunliao Bay in Huizhou, Guangdong, have gained popularity among clean-air seekers.
"Xunliao Bay is a very small and quiet place in Guangdong province. No one wanted to visit there before, because it doesn't have any famous scenic spots," said Wang Zhenyue, the deputy director of UTour International Travel Service's direct-marketing center.
"However, with many elderly people and children wanting to find a peaceful place to rest and stay away from smog, it becomes a perfect choice."