Poschiavino is an 30-kilometre (19 mi) long river that rises in the Swiss canton of Graubünden and flows into the Italian province of Sondrio. The majority of the river is in Switzerland, with just 3 kilometres (1.9 mi) in Italy.

The source of the river lies at 2,260 metres (7,410 ft) above sea level in the Rhaetian Alps, close to the Livigno Pass. From here the river flows south through the upper Val Poschiavo, past the settlements of La Rösa, Poschiavo and Le Prese, before entering the 2.5 kilometres (1.6 mi) long Lago di Poschiavo. Below the lake, the river passes the settlements of Brusio and Campocologno before crossing the border into Italy. It flows into the Adda in Tirano, at 441 metres (1,447 ft) above sea level.

The water of the river and its tributaries is used to power several hydro-electric plants owned by Repower AG.