"Roaming charges overseas are more than 10 times higher than in China," Ctrip's tourism department's marketing director Dai Yu says.

Roughly 76 percent of Chinese tourists take advantage of free Wi-Fi at hotels, restaurants and cafes, the report says. But free Wi-Fi isn't always available, even in regions with advanced telecommunications, such as the United States and Europe.

Portable Wi-Fi costs 15-50 yuan a day, depending on the country. It's cheaper in South Korea, Japan and Thailand than in much of the West.

The report points out having Wi-Fi enticed more than 40 percent of travelers to double their time online.

It says 16 percent of tourists use Wi-Fi to chat with friends and family; 16 percent use it for maps and directions; 15 percent upload photos on social media; 12 percent use it to find information about destinations; 11 percent keep up with news; and 6 percent book hotels.

A growing number of travel agencies offer increasingly diverse Wi-Fi services.

Ctrip leases Wi-Fi transmitters at airports that offer unlimited data for about 20 yuan a day on average in more than 100 countries, Dai says. The company plans to make mobile Wi-Fi an integral part of its business model, she says.

"We've seen our Wi-Fi business surge thanks to reasonable pricing and smooth surfing," Dai says.

"More suppliers are entering the market."

Travel website Tuniu.com also launched a Wi-Fi phone service in 2013. More than 100,000 people used the service last year, the company's media officer Sun Libin says.