You must show both. Showing the ticket is mandatory and the card proves your identity as a resident. You should have both with you when entering 516 Arouca.
Entry to 516 Arouca requires the purchase tickets. Buy your tickets now to guarantee your visit. Tickets are limited and they are not sold at the entrance of the bridge. The ticket for 516 Arouca also includes the visit to Passadiços do Paiva (Areinho – Vau), as long as the visit takes place in the same day. In case you choose the last visit of the day to the bridge, and if you want to make the Walkways, it is compulsory to visit them before visiting the bridge.
You must show both. Showing the ticket is mandatory and the card proves your identity as a resident. You should have both with you when entering 516 Arouca.