Forty kilometres south of Manzanillo, Cuyutlán is a sleepy black-sand beach town strung along a lagoon of the same name. It is best known for the Ola Verde, a seasonal big wave that arrives in late April and May, and for the Tortugario turtle sanctuary on the lagoon, which rescues and releases olive ridley and leatherback turtles.
The turtle centre is open daily and runs evening releases of hatchlings in season. The beach itself is wide, often deserted outside Easter week, and good for an afternoon walk with a beer at one of the palapas. The historic 19th-century salt works on the lagoon are also worth a quick look.