Outbound tour agents said the recent Bodh Gaya bombing at the Mahabodhi Temple, a Unesco World Heritage Site in India, would have some psychological effects on Thais who plan to visit the place in the upcoming high season.
"The situation will get worse if there is a new explosion at the same place. Some Thai tourists might cancel their trips due to safety concerns," said Suthipong Phuenphiphop, president of the Thai Travel Agents Association (TTAA).
"We're concerned about this issue because it's sensitive for Buddhists."
The high tourism season in India runs from October to April.
The TTAA started seriously promoting Buddhist pilgrimage tours in India in 2010. The Bodh Gaya complex is one of the most popular pilgrimage routes for Thai Buddhists.
It's one of four important places related to the life of Lord Buddha that Buddhists are recommended to visit once over the course of their life.
"If the investigation finds no link to a terrorist attack, Thais can continue to visit these sites as usual," said Mr Suthipong.
The four important places for a Buddhist pilgrimage include Bodh Gaya, in the Indian state of Bihar; Sarnath, the deer park where Gautama Buddha first taught the Dharma; Lumbini, his birthplace in Nepal; and Kusinara, where he died.
Mr Suthipong said the association estimated the number of Thai travellers enjoying pilgrimage tours in India will exceed 100,000 this year, up from 80,000 in 2009.
Narierut Pantong, managing director of Nisco Travel, said the incident should make the Indian government take serious precautions at tourist destinations to restore tourist confidence.
"The bombing will surely hurt tourist numbers for the time being, but Buddhists will likely return once things are back to normal," she said.