The Voidomatis is considered one of the cleanest rivers in Europe — glacially cold (around 6°C year-round), crystal-clear, and running through the lower reaches of the Vikos-Aoos National Park. Rafting trips on the river depart from the village of Aristi and run for about 9 kilometres through a landscape of plane trees, limestone cliffs, and the occasional ruined Ottoman bridge.
The river is rated Class II — manageable for beginners and families, and genuinely beautiful even for those more interested in scenery than white-water. You pass the ruins of the 16th-century Agion Anargiron Monastery and the arched bridge of Klidonia along the route. Several operators in Aristi and Ioannina organise trips from spring through autumn; expect about three hours including briefing and transport.