San Giovanni Suergiu, Santu Giuanni de Suergiu in sardinian language, is a comune (municipality) in the Province of Carbonia-Iglesias in the Italian region Sardinia, located about 50 kilometres (31 mi) west of Cagliari and about 4 kilometres (2 mi) south of Carbonia.
San Giovanni Suergiu borders the following municipalities: Carbonia, Giba, Portoscuso, Sant'Antioco, Tratalias.
- Church of St. Mary of Palmas, in Pisan-Romanesque style (12th century)
- Church of St. John the Baptist (14th century)
- Remains of the Castle of Palmas (11th century)
- Neolithic necropolis of Locci Santu, belonging to the Ozieri culture and including 13 domus de janas
- Several nuraghe and the giants' grave of Craminalana
- Natural preserve of Punt'e Trettu
- ^ All demographics and other statistics: Italian statistical institute Istat.