The Sepon River (Vietnamese: Sông Sepon, Lao: Se Pon) is a small river at Lao Bao town border area of Quang Tri Province, Vietnam. It forms a border between Vietnam and Laos. One side of the river belongs to Vietnam and other belongs to Laos. The river is located near the Savannakhet Province of Laos.
The Sepon River is 1 m deep and approximately 100 m wide. The water is very fresh and clean in the summer because it is not located near any industrial center. Surrounding the Sepon River is a lot of jungle with tall, large trees.
The Sepon River belongs to Huong Hoa, Lao Bao district and also the Savannakhet Province of Laos. Therefore, it is a main artery for the two provinces near there (Lao Bao and the city of Savannakhet). It is used for buying and exchange trade and commerce in Lao Bao and Savan of Laos. Every day, there are several motor boat to-and-fro here for supplying goods coming to Lao Bao town. The Sepon is regarded as a trade bridge linking Vietnam and Thailand, in order to exchange trade. In addition, one can come cross into Laos from Vietnam border by motorboat, which takes about 30 minutes to the Savan Province of Laos.