Sekolah Rendah Piasau-Piasau was officially opened on the 4th of February 1957, by YTM Seri Paduka Pengiran Bendahara Seri Maharaja Permaisuara Muda Haji Hashim Ibnu Al-Marhum Duli Pengiran Anak Abdul Rahman. The villagers of Kg. Piasau-Piasau, under the watchful eyes of the Head Village Awg Diris bin Raya, started building the school in January the same year.
The first building was made entirely of wood. The frame was made from Kayu Ramuan Bulat. The walls and roof were made from Nipah leaves.
There were 20 pupils at the start of the year, with 14 boys and 6 girls attending. This is more or less the average number of pupils for years, even until today.