The two turtles were spotted in a pond at Ban Khang Chai community in the province on Monday.
To ensure the turtles' safety, a local Saithong Kukruean subsequently sent those turtles back to Wiang Kosai National Park chief Prawit Chaikham.
"The turtles were found when my family and I drained a pond near Mae Koeng creek to catch fish for sale," Saithong said.
As the two big-headed turtles were found to be healthy and unscathed, the national park officials released them at the seventh level of Mae Koeng Luang Waterfall.
The national park also asked people who found rare animals to return them to officials, so that the animals would be able to live safely.
The big-headed turtle weighs only around half a kilogram, and could be up to 17 centimetres long.
Its characteristics include small and flat carapace, a big head, a long tail, a parrot beak-like mouth, and claw feet that enable it to climb logs or rocks.
This turtle is mostly found in the Indochina region. In Thailand, the turtle is mostly found in Loei, Phetchabun, Sakon Nakhon and Nan provinces. It eats fish, shrimp, shell, crab and frog.
The big-headed turtle has been listed as threatened species under the International Union for Conservation of Nature and the Convention on International Trade in Endangered Species of Wild Fauna and Flora.