At around 1:30 p.m. Ngo Nguyen Ngoc Huong, 13, and her two sisters aged seven and nine went to the Ba Du River in Cao Lanh District.
When they did not return home for long their family went to the river to look for them.
Locals found the bodies of two children, and rescue workers found the third at around 8:40 p.m.
Tragically, there have been frequent cases of children drowning in the country, especially during summertime.
Just three days earlier three siblings in the central province of Ninh Thuan drowned in a pond near their home, and a week before that four children playing in a channel of the Quao River in Binh Thuan Province nearby were swept away and drowned.