Once, the mere mention of Chinese tourists would conjure images of giant tour buses disgorging clueless travellers into overpriced souvenir shops and sub-standard restaurants at the fringe of some of Thailand's largest attractions.

Today's travellers are more independent. They book their own lodgings, and dine in fine restaurants as readily as they pose for selfies at quaint spots in backstreets.

According to the Tourism Authority of Thailand, 39.5 per cent of Chinese visitors arrived via group tours in 2015. About a quarter relied on social media for travel choices; roughly the same proportion consulted friends.

The language barrier is no deterrent. Two retired teachers from Liaoning province, for example, went by car to the border with Vietnam and headed south by bus, before crossing into Cambodia to see Angkor Wat and ending their trip in Bangkok. "We don't really speak English, so we used hand gestures sometimes," said one of them, who wanted to be known as Ms Feng.

Chinese arrivals have tripled over four years, making them the biggest source of tourists.

Thailand is the top destination for Chinese tourists in South-east Asia. Last year, 8.76 million visited, against 3.53 million Malaysians and 1.4 million South Koreans.

The numbers could have topped 10 million, but the government cracked down on "zero-dollar" operators from China offering cheap packages to budget travellers, who would have to stay and shop in places tightly controlled by a network.

Tourism accounted for about 11 per cent of Thai GDP in 2015. The tourism authority expects 9.8 million Chinese visitors this year.

At Clover pharmacy and souvenir shop in Bangkok, speaking Chinese is a job requirement. Prices are in Chinese; notices explain in Chinese how to get purchases delivered.

Organic latex pillows going for about 2,000 baht (S$80) apiece are hot items; so are snacks like fried seaweed. Food, shopping and beaches are the top draws.

Increasingly, Chinese travellers buy souvenirs only if they have been positively reviewed by other Chinese travellers online.

"They are more rational now - before, they would turn up and buy everything," says Ms Macy Miao, a Bangkok-based Chinese national who works at travel agency OMT Education and Travel.

Smartphone-based online payment systems like Alipay and WeChat Pay are now available at duty-free retailer King Power and 7-Eleven stores.