The Passadiços do Paiva is an 8.7-kilometre boardwalk trail that follows the Paiva River through a deep, forested gorge between Espiunca and Areinho. The trail winds through forest, crosses the river on suspension footbridges, and passes waterfalls and exposed rock formations. The river runs fast and clear; on warm days people swim in the pools. It is one of the best marked and best maintained trails in Portugal.
The trail is mostly flat but has stretches with significant steps and elevation change — expect around 400 metres of ascent in total. Allow three to four hours for the one-way walk. Most people either arrange a shuttle back or walk it in both directions; the 516 Arouca bridge is at the Areinho end and makes a natural endpoint. Start early: the trail is one-way (Espiunca to Areinho) and can be busy. Bring water and good footwear — the wooden boards can be slippery in the wet.