A truckload of protected animals, including more than 350 turtles and 100 snakes, was seized in in Muang district of Khon Kaen on Friday.
Highway police arrested driver Phumin Thanamai, 56, and Wallop Naruemitprachakorn, 41, after stopping their vehicle for a search in front of the second Khon Kaen bus terminal at 1am.
Police found 359 turtles, nine soft-shelled turtles and 100 monitor lizards as well as more than 100 king cobras, water snakes and pythons.
Pol Lt Col Padol Jandon, a highway police officer, said the suspects tried to bribe officers not to take action against them.
The pair told officers they were hired for 60,000 baht to transport the animals from a market in Bangkok to Nong Khai province, Pol Lt Col Padol said.
The animals were to be transported across the Mekong River and sold abroad, and their sale could have fetched more than 1.5 million baht, the officer said.
Police have not yet found out where the animals were taken from.
The animals will be taken to a national park office in Khon Kaen pending further investigation, Pol Lt Col Padol said.