Close to the beautiful Westerwald Hills, Diez welcomes travellers from all walks of life. There is ample opportunity for sports activities and well-developed routes for cyclists mean that this proves particularly popular. The Aprospos Lahn, the river that runs close to the town, is widely regarded as one of the most beautiful and unspoilt in Germany. There are many attractions to be seen in Diez. These include the Schloss Schaumburg or Lauren Castle, as well as the alleys of the Diez Altstadt. One of the highlights of the town is the castle, Nassau-Diez, which dominates the landscape.

Particular highlight for culture buffs are the Orange Steinger concerts that are held regularly, and also the Lime Works Festival. For an alternative attraction, visitors may also want to see the gravel pit at Herthasee. Visitors can take in the harmonious areas surrounding the town from here, including the many valleys and picturesque villages.