Their kids' footprints have been left on hundreds of destinations in over 20 countries.

"Products that just scratch the surface, like simple tours of famous universities, have fallen out of favor with the market," Zhang says.

Language training, NASA's space camp, computer programming, homestays, wild animal care and desert and museum experiences are among the most popular options.

"Certain volunteering and public-welfare routes have seen a particularly fast increase in bookings," Zhang says.

During the recent winter vacation in February, study-trip bookings surged by 80 percent compared with the same period of last year.

Domestic trips cost roughly 4,500 yuan ($663) per capita on average, while expenditures hit 21,000 yuan for outbound experiences, the agency reports.

Parents from Shanghai, Beijing and Guangdong province's Guangzhou and Shenzhen are the most willing to spend, according to Ctrip's data.

Wang Chunyan has arranged to take her son on study tours since 2015.

"We've been to deserts, grasslands and (sections of) the Silk Road over the years," Wang says.

Wang has booked for her son－who is currently in the fifth grade－a two-week trip to Australia and a two-week trip to the US in August.

"He will be sitting in local classes and studying with local children there," Wang says.