A two-month-old tiger cub has been found sedated and hidden among stuffed toy tigers in a woman's luggage at Bangkok's airport, the wildlife trade monitoring network Traffic has said.
The Thai national was trying to board a flight to Iran but had difficulty with a large bag at check-in.
X-rays aroused suspicions among airport staff who believed they had seen an image resembling a real animal.
Wildlife officers were then called in and discovered the tranquilised cub.
The tiger was found last Sunday and is now being cared for at the rescue centre of the department of national parks, wildlife and plant conservation.
Authorities are trying to determine if the cat is wild or captive-bred.
Chris Shepherd, South-East Asia deputy regional director for Traffic, said: "We applaud all the agencies that came together to uncover this brazen smuggling attempt."
But he also called for regular monitoring and harsher penalties.
"If people are trying to smuggle live tigers in their check-in luggage, they obviously think wildlife smuggling is something easy to get away with and do not fear reprimand," he said.
"Only sustained pressure on wildlife traffickers and serious penalties can change that."