On the southwestern shore of Las Cabezas' peninsula, Playa Seven Seas is a sheltered, palm-shaded, horseshoe-shaped public beach. Quiet at times, it gets packed on weekends and during summer and people don't always take their trash. Beach chairs, umbrellas, snorkel gear and kayaks can be rented from beach vendors, and there are kioskos and restaurants nearby if you get hungry.
For good snorkeling, follow the beach about a half mile to the northeast off Hwy 987 (aka Hidden Beach); the reefs are just offshore. For a quiet spot, head west on the well-marked trail from Playa Seven Seas to the pretty Playa El Convento, where you'll likely have the beach to yourself.