Sai Yok National Park covers an area in both Thong Pha Phum District and Sai Yok District in Kanchanaburi Province. It spans approximately 500 square kilometers, or 312,500 rai. The park's landscape is predominantly made up of mixed deciduous and dry evergreen forests. Sai Yok National Park serves as a crucial habitat for two rare species: the Kitti's hog-nosed bat, the smallest bat in the world, and the three-colored crab, also known as the queen crab, which is a newly discovered freshwater species.