Praia de Montalvo is the long sweep of sand running west from Portonovo. At over a kilometre it is one of the bigger beaches on this stretch of coast, with low dunes, pine woods behind, and reliably clean water — Blue Flag most years. It feels less developed than Silgar; there are fewer buildings on the road behind, and the noise level is correspondingly lower.
On the south side of Montalvo the rocks separate it from the smaller, prettier Canelas beach, reached by a short path. A walk over those rocks at the right tide gives you a private-feeling cove between two larger beaches. There is parking, a beach bar, and the usual lifeguard service in season.