Sai Yok Waterfall (Thai: น้ำตกไทรโยค), located 104 km northwest of Kanchanaburi town, is the most popular attraction in the 500-sq-km Sai Yok National Park. Popularized in poetry and a classic Thai song, the Sai Yok and Sai Yok Noi falls cascade directly into the Khwae Noi River, close to the National Park headquarters to the west of Highway No 323. A wire rope suspension bridge has been strung across the river opposite the falls to give visitors a clear view. The sand bar on the opposite bank from the falls also affords a direct view.
Sai Yok Noi (Thai: ไทรโยคน้อย) is a waterfall in the Sai Yok district of Kanchanaburi Province, near the small town Nam Tok Sai Yok Noi. It is the most popular attraction of the Sai Yok National Park for domestic and foreign tourists alike, in part because it lies next to the province’s trunk road alongside which there is ample parking space. The immediate vicinity features several sites of interest including the Krasae Cave, a small Buddhist shrine next to a section of rail tracks of the notorious Death Railway and, to the west, Daowadung Cave, a secluded collection of impressive stalactites. Hellfire Pass Memorial, a museum and tribute to those lost during the construction of the Death Railway’s cuttings and trestle bridges, lies about 35 km to the west of Sai Yok Noi falls. A small market geared toward travelers is also nearby. Sai Yok Yai waterfall, some 40 km to the west lies offset from the valley’s main road, adjacent to the Sai Yok National Park Headquarters. It comprises a 10 meter (32 ft) picturesque cascade which drops directly into the Khwae Noi River (Thai: แม่น้ำแควน้อย).
Other attractions in the Sai Yok National Park include fascinating limestone caves, which are home to the Kitti's hog-nosed bat, discovered in 1973 and reckoned to be the world's smallest mammal at just 3 cm (1 inch) in length. Wildlife in the area includes 67 bird species, barking deer, slow loris, gibbons, porcupines, serow and wild elephants. Tropical broad-leaved evergreen forests cover most of the park, while bamboo and mixed deciduous tracts can be found in the lowlands and foothills.
Sai Yok was the site of a Japanese army barracks during the Second World War and traces of the soldiers' camps and the abandoned Death Railway can still be seen. Most of the rails and sleepers of the railway have been claimed by local villagers.
Rafts can be hired from Sai Yok to explore the limpid Khwae Noi and to get to the Daowadung (to the north) and Lawa (to the south) caves with their exquisite stalactites and stalagmites. Some of the unforgettable Russian roulette scenes in the film 'The Deer Hunter' were shot on the river in this area.
Accommodation in the form of raft houses and National Park bungalows is available close to the park headquarters. The place is popular at the weekend so expect to pay more than in the week. Sai Yok National Park can be reached by bus or car from Kanchanaburi or by train to Sai Yok and then bus. It's also possible to charter a boat from Kanchanaburi for the 100-km trip upstream.