The Otava (German Wottawa) is a river in West and South Bohemia, Czech Republic. It is a left tributary of the Vltava. It is 112 kilometres (70 mi) long, and its basin area is about 3,840 square kilometres (1,480 sq mi), of which 3,827 square kilometres (1,478 sq mi) in the Czech Republic. The river flows through several towns, including Sušice, Strakonice and Písek. The river's name is of Celtic origin. It is a popular river for water sports. The local dialect of Prachens also uses the name "Wotāva".