Nong Thung Thong (Thai: หนองทุ่งทอง) is a swamp on the east bank of the Tapi River in Khian Sa District, Surat Thani Province, southern Thailand.
The area, together with the Nong Tung Ka on the west bank of the river, forms a complex of grassland and swamps along the river. During the end of the southwest monsoon and during the northeast monsoon (October–December) the area is almost completely flooded, while at the end of the dry season (March) most of the area is dry.
In 1975 an area of 29.6 km2 was declared a non-hunting area. In 1989 it was enlarged to 64.5 km2.