Playa Negra ("black beach") is a long dark-sand beach just north of Puerto Viejo, named for the volcanic origin of the sand. It's a five-minute walk or bike ride from the town centre, and tends to be quieter than the southern beaches.
The sea here is rougher than at Punta Uva but calmer than the Salsa Brava break, which makes it a reasonable place for a swim with care. Leatherback turtles nest along this stretch of coast between February and July, and the local ATEC community organisation runs night patrols and nest protection — they take visitors during the season.