San Blas [1]’s most convenient beach is Playa el Borrego, at the south end of Calle Cuauhtémoc about a mile south of town. With a lineup of palapas for food and drinks, the mile-long broad, fine-sand beach is ripe for all beach activities except snorkeling (because of the murky water).
The mild offshore currents and gentle, undertow-free slope of are nearly always safe for good swimming, bodysurfing, and boogie boarding. Surfing is especially popular here and conditions are often right for good sailboarding.
Shoals of shells—clams, cockles, mother-of-pearl—wash up on Borrego Beach during storms. Fishing is often good, especially when casting from the jetty and rocks at the north and south ends.
Links:
[1] http://www.moon.com/destinations/puerto-vallarta/the-nayarit-coast/san-blas-and-vicinity