Nudists, grab your yoga mats and head for San Francisco.

City prosecutors said it was not illegal to perform naked yoga in the city - even at the crowded tourist destination of Fisherman's Wharf.

Prosecutors dropped charges against a limber nudist, known locally as the "Naked Yoga Guy," who made a habit of striking yoga poses in the buff in order to promote a book and his lifestyle.

The Naked Yoga Guy, whose name is George Monty Davis, had stripped to stretch nearby Fisherman's Wharf, prompting a public complaint. But prosecutors decided they had a weak public nuisance case against him because local laws do not bar public nudity.

"Simply being naked on the street is not a crime in San Francisco," said Debbie Mesloh, a spokeswoman for the district attorney's office.

"To bring a case, a person would have to exhibit lewd behavior, block traffic or impede pedestrians on a sidewalk, something along those lines."