San Blas has a surf reputation that goes back to the 1960s, when it appeared in the Beach Boys song "Surfin' USA" as one of the great surf spots of the world (though the Beach Boys' geography was not always reliable). The point breaks in Matanchen Bay, about 10 km south of town, produce long waves that can run for several hundred metres — some reports place them among the longest in Mexico.
The main break at Stoner's Point in Matanchen is best for experienced surfers. The beach at Las Islitas, further into the bay, offers gentler waves suitable for beginners. Board rentals and lessons are available from local operators during the main season (October through April, when the northwest swells arrive). The no-see-um gnats (jejenes) that plague San Blas are less problematic on the beach with a sea breeze than in town.