Vostervatnet is a lake in the municipality of Strand in Rogaland county, Norway. The 2.62-square-kilometre (1.01 sq mi) lake lies in the northwestern part of Strand, just south of the Fognafjorden. The village of Tau lies about 3.5 kilometres (2.2 mi) southwest of the lake. The main outflow of the lake is the river Fiskåna, which flows north from the northeastern corner of the lake, down the hill to the village of Fiskå on the shore of the fjord.

• List of lakes in Norway