Puerto Escondido is a surf town, and the first thing to understand is which wave you are talking about.
Zicatela, the Mexican Pipeline, is a world-class beach break that closes out hard and shallow. It breaks big from roughly April to October, it has a serious injury record, and it is not a wave to learn on or to swim at. Lifeguards pull people out of it regularly.
La Punta, at the southern end of the same beach, is where the swell wraps around a point and becomes a long, forgiving left. That is where beginners go. Carrizalillo, a small cove reached by a long flight of steps, is gentler still and the usual venue for a first lesson.
Away from the surf, the bioluminescence in the Laguna de Manialtepec north of town is extraordinary on a moonless night, and the lagoon is also serious birdwatching. Boats run out at dawn to see dolphins, turtles and — from December to March — humpback whales. Sport fishing leaves from Puerto Angelito, and turtle releases happen on the beaches east of town in nesting season.