Praia do Porto Santo is the island's reason for being in most travel plans. The beach runs for kilometres along the south coast, with soft golden sand and water that feels startlingly easy after Madeira's rockier, rougher shoreline. It is not wild or secret, but it is generous.
Near Vila Baleira the beach has the most services and the easiest access. Walk west and it becomes quieter, with the scale of the sand, dunes, and pale hills taking over. If you are coming from Madeira for one day, this is where most of that day will go.